Update CHANGELOGs

Add slashes to base URLs
Merge pull request #280 from 0xProject/feature/updateReadmes
2017-12-20 16:40:19 +01:00 · 2017-12-20 16:25:41 +01:00 · 2017-12-20 10:06:44 -05:00 · 2017-12-20 15:33:15 +01:00 · 2017-12-20 15:21:36 +01:00 · 2017-12-20 15:18:15 +01:00
608 changed files with 48912 additions and 3238 deletions
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -5,7 +5,7 @@ jobs:
    docker:
      - image: circleci/node:6.12
    environment:
-      CONTRACTS_COMMIT_HASH: '78fe8dd'
+      CONTRACTS_COMMIT_HASH: '9ed05f5'
    steps:
      - checkout
      - run: echo 'export PATH=$HOME/CIRCLE_PROJECT_REPONAME/node_modules/.bin:$PATH' >> $BASH_ENV
@@ -19,7 +19,7 @@ jobs:
      - run: wget https://s3.amazonaws.com/testrpc-shapshots/${CONTRACTS_COMMIT_HASH}.zip
      - run: unzip ${CONTRACTS_COMMIT_HASH}.zip -d testrpc_snapshot
      - run: node ./node_modules/lerna/bin/lerna.js bootstrap
-      - run: yarn lerna:run bootstrap
+      - run: yarn lerna:run build
      - run:
          name: testrpc
          command: npm run testrpc -- --db testrpc_snapshot
--- a/.gitignore
+++ b/.gitignore
@@ -63,4 +63,11 @@ lib/
 _bundles

 # generated documentation
-docs/
+generated_docs/
+
+TODO.md
+
+packages/website/public/bundle*
+
+# generated binaries
+bin/
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -42,7 +42,7 @@ We also recommend you read through the tests.

 ## Styleguide

-We use `[tslint](https://palantir.github.io/tslint/)` with [custom configs](https://github.com/0xProject/tslint-config-0xproject) to keep our code style consistent.
+We use [TSLint](https://palantir.github.io/tslint/) with [custom configs](https://github.com/0xProject/tslint-config-0xproject) to keep our code style consistent.

 To lint your code just run: `yarn lint`

--- a/README.md
+++ b/README.md
@@ -17,11 +17,88 @@ This repository contains all the 0x developer tools written in TypeScript. Our h
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 [![Greenkeeper badge](https://badges.greenkeeper.io/0xProject/0x.js.svg?token=7c22e5c72acf39d3ead8d29c5d9bb38f9096df3e643024dcedd53ab732847be1&ts=1496426342666)](https://greenkeeper.io/)

-### Core Packages
+### Published Packages

 | Package | Version | Description |
-|--------|-------|------------|
-| [`0x.js`](/packages/0x.js) | [![npm](https://img.shields.io/npm/v/0x.js.svg?maxAge=2592000)](https://www.npmjs.com/package/0x.js) | A Javascript library for interacting with the 0x protocol |
-| [`@0xproject/assert`](/packages/assert) | [![npm](https://img.shields.io/npm/v/@0xproject/assert.svg?maxAge=2592000)](https://www.npmjs.com/package/@0xproject/assert) | Standard type and schema assertions |
-| [`@0xproject/json-schemas`](/packages/json-schemas) | [![npm](https://img.shields.io/npm/v/@0xproject/json-schemas.svg?maxAge=2592000)](https://www.npmjs.com/package/@0xproject/json-schemas) | 0x-related json schemas |
-| [`@0xproject/tslint-config`](/packages/tslint-config) | [![npm](https://img.shields.io/npm/v/@0xproject/tslint-config.svg?maxAge=2592000)](https://www.npmjs.com/package/@0xproject/tslint-config) | Custom 0x project TSLint rules |
+|---------|---------|-------------|
+| [`0x.js`](/packages/0x.js) | [![npm](https://img.shields.io/npm/v/0x.js.svg)](https://www.npmjs.com/package/0x.js) | A Javascript library for interacting with the 0x protocol |
+| [`@0xproject/abi-gen`](/packages/abi-gen) | [![npm](https://img.shields.io/npm/v/@0xproject/abi-gen.svg)](https://www.npmjs.com/package/@0xproject/abi-gen) | Tool to generate TS wrappers from smart contract ABIs |
+| [`@0xproject/assert`](/packages/assert) | [![npm](https://img.shields.io/npm/v/@0xproject/assert.svg)](https://www.npmjs.com/package/@0xproject/assert) | Type and schema assertions used by our packages |
+| [`@0xproject/connect`](/packages/connect) | [![npm](https://img.shields.io/npm/v/@0xproject/connect.svg)](https://www.npmjs.com/package/@0xproject/connect) | A Javascript library for interacting with the standard relayer api |
+| [`@0xproject/json-schemas`](/packages/json-schemas) | [![npm](https://img.shields.io/npm/v/@0xproject/json-schemas.svg)](https://www.npmjs.com/package/@0xproject/json-schemas) | 0x-related json schemas |
+| [`@0xproject/subproviders`](/packages/subproviders) | [![npm](https://img.shields.io/npm/v/@0xproject/subproviders.svg)](https://www.npmjs.com/package/@0xproject/subproviders) | Useful web3 subproviders (e.g LedgerSubprovider) |
+| [`@0xproject/tslint-config`](/packages/tslint-config) | [![npm](https://img.shields.io/npm/v/@0xproject/tslint-config.svg)](https://www.npmjs.com/package/@0xproject/tslint-config) | Custom 0x development TSLint rules |
+| [`@0xproject/types`](/packages/types) | [![npm](https://img.shields.io/npm/v/@0xproject/types.svg)](https://www.npmjs.com/package/@0xproject/types) | Shared type declarations |
+| [`@0xproject/utils`](/packages/utils) | [![npm](https://img.shields.io/npm/v/@0xproject/utils.svg)](https://www.npmjs.com/package/@0xproject/utils) | Shared utilities |
+| [`@0xproject/web3-wrapper`](/packages/web3-wrapper) | [![npm](https://img.shields.io/npm/v/@0xproject/web3-wrapper.svg)](https://www.npmjs.com/package/@0xproject/web3-wrapper) | Web3 wrapper |
+
+### Private Packages
+
+| Package | Description |
+|---------|-------------|
+| [`@0xproject/contracts`](/packages/contracts) | 0x solidity smart contracts & tests |
+| [`@0xproject/kovan_faucets`](/packages/kovan-faucets) | A faucet micro-service that dispenses test ERC20 tokens or Ether |
+| [`@0xproject/monorepo-scripts`](/packages/monorepo-scripts) | Shared monorepo scripts |
+| [`@0xproject/website`](/packages/website) | 0x website & Portal DApp |
+
+## Usage
+
+Dedicated documentation pages:
+- [0x.js Library](https://0xproject.com/docs/0xjs)
+- [0x Connect](https://0xproject.com/docs/connect)
+- [Smart contracts](https://0xproject.com/docs/contracts)
+- [Standard Relayer API](https://github.com/0xProject/standard-relayer-api/blob/master/README.md)
+
+## Contributing
+
+We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
+
+Please read our [contribution guidelines](./CONTRIBUTING.md) before getting started.
+
+### Install dependencies
+
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
+```bash
+yarn config set workspaces-experimental true
+```
+
+Then install dependencies
+```bash
+yarn install
+```
+
+### Build
+
+Build all packages
+
+```bash
+yarn lerna:run build
+```
+
+### Lint
+
+Lint all packages
+```bash
+yarn lerna:run lint
+```
+
+### Run Tests
+
+Before running the tests, you will need to spin up a [TestRPC](https://www.npmjs.com/package/ethereumjs-testrpc) instance and deploy all the 0x smart contracts.
+
+In a separate terminal, start TestRPC (a convenience command is provided as part of this repo)
+```bash
+yarn testrpc
+```
+
+Then in your main terminal run
+```
+cd packages/contracts
+yarn migrate
+cd ..
+```
+
+And finally from the root project directory run
+```bash
+yarn lerna:run test
+```
--- a/package.json
+++ b/package.json
@@ -7,16 +7,18 @@
    "scripts": {
        "testrpc": "testrpc -p 8545 --networkId 50 -m \"${npm_package_config_mnemonic}\"",
        "lerna:run": "lerna run",
-        "lerna:publish": "lerna run clean; lerna run build; lerna publish"
+        "lerna:rebuild": "lerna run clean; lerna run build;",
+        "lerna:publish": "yarn install; lerna run clean; lerna run build; lerna publish --registry=https://registry.npmjs.org/"
    },
    "config": {
-      "mnemonic": "concert load couple harbor equip island argue ramp clarify fence smart topic"
+        "mnemonic": "concert load couple harbor equip island argue ramp clarify fence smart topic"
    },
    "devDependencies": {
-        "lerna": "^2.5.1",
+        "@0xproject/utils": "^0.1.0",
        "async-child-process": "^1.1.1",
-        "semver-sort": "^0.0.4",
+        "ethereumjs-testrpc": "6.0.3",
+        "lerna": "^2.5.1",
        "publish-release": "0xproject/publish-release",
-        "es6-promisify": "^5.0.0"
+        "semver-sort": "^0.0.4"
    }
 }
--- a/packages/0x.js/CHANGELOG.md
+++ b/packages/0x.js/CHANGELOG.md
@@ -1,6 +1,34 @@
 # CHANGELOG

-v0.26.0
+v0.28.0 - _December 20, 2017_
+------------------------
+    * Add `etherTokenAddress` arg to `depositAsync` and `withdrawAsync` methods on `zeroEx.etherToken` (#267)
+    * Removed accidentally included `unsubscribeAll` method from `zeroEx.proxy`, `zeroEx.etherToken` and `zeroEx.tokenRegistry` (#267)
+    * Removed `etherTokenContractAddress` from `ZeroEx` constructor arg `ZeroExConfig` (#267)
+    * Rename `SubscriptionOpts` to `BlockRange` (#272)
+    * Add `zeroEx.etherToken.subscribe`, `zeroEx.etherToken.unsubscribe`, `zeroEx.etherToken.unsubscribeAll` (#277)
+    * Add `zeroEx.etherToken.getLogsAsync` (#277)
+    * Add new public types `BlockParamLiteral`, `EtherTokenEvents`, `EtherTokenContractEventArgs`, `DepositContractEventArgs`, `WithdrawalContractEventArgs` (#277)
+    * Support `Deposit` and `Withdraw` events on etherToken (#277)
+    * Improve the error message when taker is not a string (#278)
+
+v0.27.1 - _November 28, 2017_
+------------------------
+    * Export `TransactionOpts` type
+
+v0.27.0 - _November 28, 2017_
+------------------------
+    * Make `ZeroExConfig` required parameter of `ZeroEx` constructor (#233)
+    * Add a required property `networkId` to `ZeroExConfig` (#233)
+    * Make all `getContractAddress` functions, `zeroEx.exchange.subscribe`, `zeroEx.exchange.getZRXTokenAddress` sync (#233)
+    * Remove `ZeroExError.ContractNotFound` and replace it with contract-specific errors (#233)
+    * Make `DecodedLogEvent<A>` contain `LogWithDecodedArgs<A>` under log key instead of merging it in like web3 does (#234)
+    * Rename `removed` to `isRemoved` in `DecodedLogEvent<A>` (#234)
+    * Add config allowing to specify gasPrice and gasLimit for every transaction sending method (#235)
+    * All transaction sending methods now call `estimateGas` if no gas amount was supplied (#235)
+    * Modify order validation methods to validate against the `latest` block, not against the `pending` block (#236)
+
+v0.26.0 - _November 21, 2017_
 ------------------------
    * Add post-formatter for logs converting `blockNumber`, `logIndex`, `transactionIndex` from hexes to numbers (#231)
    * Remove support for Async callback types when used in Subscribe functions (#222)
--- a/packages/0x.js/contract_templates/contract.mustache
+++ b/packages/0x.js/contract_templates/contract.mustache
@@ -0,0 +1,26 @@
+/**
+ * This file is auto-generated using abi-gen. Don't edit directly.
+ * Templates can be found at https://github.com/0xProject/0x.js/tree/development/packages/abi-gen-templates.
+ */
+// tslint:disable-next-line:no-unused-variable
+import {TxData, TxDataPayable} from '@0xproject/types';
+import {classUtils, promisify} from '@0xproject/utils';
+import {BigNumber} from 'bignumber.js';
+import * as Web3 from 'web3';
+
+import {BaseContract} from './base_contract';
+
+export class {{contractName}}Contract extends BaseContract {
+{{#each methods}}
+    {{#this.constant}}
+    {{> call contractName=../contractName}}
+    {{/this.constant}}
+    {{^this.constant}}
+    {{> tx contractName=../contractName}}
+    {{/this.constant}}
+{{/each}}
+    constructor(web3ContractInstance: Web3.ContractInstance, defaults: Partial<TxData>) {
+        super(web3ContractInstance, defaults);
+        classUtils.bindAll(this, ['web3ContractInstance', 'defaults']);
+    }
+} // tslint:disable:max-file-line-count
--- a/packages/0x.js/contract_templates/partials/call.mustache
+++ b/packages/0x.js/contract_templates/partials/call.mustache
@@ -0,0 +1,15 @@
+public {{this.name}} = {
+    async callAsync(
+    {{> typed_params inputs=inputs}}
+        defaultBlock?: Web3.BlockParam,
+    ): Promise<{{> return_type outputs=outputs}}> {
+        const self = this as {{contractName}}Contract;
+        const result = await promisify<{{> return_type outputs=outputs}}>(
+            self.web3ContractInstance.{{this.name}}.call,
+            self.web3ContractInstance,
+        )(
+            {{> params inputs=inputs}}
+        );
+        return result;
+    },
+};
--- a/packages/0x.js/contract_templates/partials/params.mustache
+++ b/packages/0x.js/contract_templates/partials/params.mustache
@@ -0,0 +1,3 @@
+{{#each inputs}}
+{{name}},
+{{/each}}
--- a/packages/0x.js/contract_templates/partials/return_type.mustache
+++ b/packages/0x.js/contract_templates/partials/return_type.mustache
@@ -0,0 +1,6 @@
+{{#singleReturnValue}}
+{{#returnType outputs.0.type}}{{/returnType}}
+{{/singleReturnValue}}
+{{^singleReturnValue}}
+[{{#each outputs}}{{#returnType type}}{{/returnType}}{{#unless @last}}, {{/unless}}{{/each}}]
+{{/singleReturnValue}}
--- a/packages/0x.js/contract_templates/partials/tx.mustache
+++ b/packages/0x.js/contract_templates/partials/tx.mustache
@@ -0,0 +1,51 @@
+public {{this.name}} = {
+    async sendTransactionAsync(
+    {{> typed_params inputs=inputs}}
+    {{#this.payable}}
+        txData: TxDataPayable = {},
+    {{/this.payable}}
+    {{^this.payable}}
+        txData: TxData = {},
+    {{/this.payable}}
+    ): Promise<string> {
+        const self = this as {{contractName}}Contract;
+        const txDataWithDefaults = await self.applyDefaultsToTxDataAsync(
+            txData,
+            self.{{this.name}}.estimateGasAsync.bind(
+                self,
+                {{> params inputs=inputs}}
+            ),
+        );
+        const txHash = await promisify<string>(
+            self.web3ContractInstance.{{this.name}}, self.web3ContractInstance,
+        )(
+            {{> params inputs=inputs}}
+            txDataWithDefaults,
+        );
+        return txHash;
+    },
+    async estimateGasAsync(
+    {{> typed_params inputs=inputs}}
+        txData: TxData = {},
+    ): Promise<number> {
+        const self = this as {{contractName}}Contract;
+        const txDataWithDefaults = await self.applyDefaultsToTxDataAsync(
+            txData,
+        );
+        const gas = await promisify<number>(
+            self.web3ContractInstance.{{this.name}}.estimateGas, self.web3ContractInstance,
+        )(
+            {{> params inputs=inputs}}
+            txDataWithDefaults,
+        );
+        return gas;
+    },
+    getABIEncodedTransactionData(
+    {{> typed_params inputs=inputs}}
+        txData: TxData = {},
+    ): string {
+        const self = this as {{contractName}}Contract;
+        const abiEncodedTransactionData = self.web3ContractInstance.{{this.name}}.getData();
+        return abiEncodedTransactionData;
+    },
+};
--- a/packages/0x.js/contract_templates/partials/typed_params.mustache
+++ b/packages/0x.js/contract_templates/partials/typed_params.mustache
@@ -0,0 +1,3 @@
+{{#each inputs}}
+    {{name}}: {{#parameterType type}}{{/parameterType}},
+{{/each}}
--- a/packages/0x.js/package.json
+++ b/packages/0x.js/package.json
@@ -1,6 +1,6 @@
 {
  "name": "0x.js",
-  "version": "0.26.0",
+  "version": "0.27.2",
  "description": "A javascript library for interacting with the 0x protocol",
  "keywords": [
    "0x.js",
@@ -12,11 +12,12 @@
  "main": "lib/src/index.js",
  "types": "lib/src/index.d.ts",
  "scripts": {
-    "prebuild": "npm run clean",
+    "prebuild": "run-s clean generate_contract_wrappers",
    "build": "run-p build:umd:prod build:commonjs; exit 0;",
    "docs:json": "typedoc --excludePrivate --excludeExternals --target ES5 --json $JSON_FILE_PATH $PROJECT_DIR",
-    "upload_docs_json": "aws s3 cp docs/index.json $S3_URL --profile 0xproject --grants read=uri=http://acs.amazonaws.com/groups/global/AllUsers --content-type aplication/json",
-    "lint": "tslint src/**/*.ts test/**/*.ts",
+    "upload_docs_json": "aws s3 cp generated_docs/index.json $S3_URL --profile 0xproject --grants read=uri=http://acs.amazonaws.com/groups/global/AllUsers --content-type application/json",
+    "generate_contract_wrappers": "node ../abi-gen/lib/index.js --abiGlob 'src/artifacts/@(Exchange|Token|TokenTransferProxy|EtherToken|TokenRegistry|DummyToken).json' --templates contract_templates --output src/contract_wrappers/generated",
+    "lint": "tslint --project . 'src/**/*.ts' 'test/**/*.ts'",
    "test:circleci": "run-s test:coverage report_test_coverage && if [ $CIRCLE_BRANCH = \"development\" ]; then yarn test:umd; fi",
    "test": "run-s clean test:commonjs",
    "test:umd": "./scripts/test_umd.sh",
@@ -30,7 +31,7 @@
    "test:commonjs": "run-s build:commonjs run_mocha",
    "pretest:umd": "run-s clean build:umd:dev build:commonjs",
    "substitute_umd_bundle": "shx mv _bundles/* lib/src",
-    "run_mocha": "mocha lib/test/**/*_test.js --timeout 5000 --bail --exit"
+    "run_mocha": "mocha lib/test/**/*_test.js --timeout 10000 --bail --exit"
  },
  "config": {
    "artifacts": "TokenTransferProxy Exchange TokenRegistry Token EtherToken"
@@ -44,27 +45,29 @@
    "node": ">=6.0.0"
  },
  "devDependencies": {
-    "@0xproject/tslint-config": "^0.1.1",
+    "@0xproject/abi-gen": "^0.0.2",
+    "@0xproject/tslint-config": "^0.2.1",
+    "@0xproject/types": "^0.1.0",
+    "@0xproject/dev-utils": "^0.0.1",
    "@types/bintrees": "^1.0.2",
    "@types/jsonschema": "^1.1.1",
-    "@types/lodash": "^4.14.64",
-    "@types/mocha": "^2.2.41",
-    "@types/node": "^8.0.1",
+    "@types/lodash": "^4.14.86",
+    "@types/mocha": "^2.2.42",
+    "@types/node": "^8.0.53",
    "@types/sinon": "^2.2.2",
    "@types/uuid": "^3.4.2",
    "awesome-typescript-loader": "^3.1.3",
    "chai": "^4.0.1",
    "chai-as-promised": "^7.1.0",
-    "chai-as-promised-typescript-typings": "0.0.3",
+    "chai-as-promised-typescript-typings": "^0.0.3",
    "chai-bignumber": "^2.0.1",
    "chai-typescript-typings": "^0.0.1",
    "copyfiles": "^1.2.0",
    "coveralls": "^3.0.0",
    "dirty-chai": "^2.0.1",
-    "ethereumjs-testrpc": "4.0.1",
    "json-loader": "^0.5.4",
-    "mocha": "^4.0.0",
-    "npm-run-all": "^4.0.2",
+    "mocha": "^4.0.1",
+    "npm-run-all": "^4.1.2",
    "nyc": "^11.0.1",
    "opn-cli": "^3.1.0",
    "request": "^2.81.0",
@@ -75,21 +78,20 @@
    "truffle-hdwallet-provider": "^0.0.3",
    "tslint": "5.8.0",
    "typedoc": "~0.8.0",
-    "types-bn": "^0.0.1",
-    "types-ethereumjs-util": "0xProject/types-ethereumjs-util",
    "typescript": "~2.6.1",
    "web3-provider-engine": "^13.0.1",
-    "web3-typescript-typings": "^0.7.1",
+    "web3-typescript-typings": "^0.7.2",
    "webpack": "^3.1.0"
  },
  "dependencies": {
-    "@0xproject/assert": "^0.0.5",
-    "@0xproject/json-schemas": "^0.6.8",
+    "@0xproject/assert": "^0.0.7",
+    "@0xproject/json-schemas": "^0.6.10",
+    "@0xproject/utils": "^0.1.0",
+    "@0xproject/web3-wrapper": "^0.1.0",
    "bignumber.js": "~4.1.0",
    "bintrees": "^1.0.2",
-    "bn.js": "4.11.8",
+    "bn.js": "^4.11.8",
    "compare-versions": "^3.0.1",
-    "es6-promisify": "^5.0.0",
    "ethereumjs-abi": "^0.6.4",
    "ethereumjs-blockstream": "^2.0.6",
    "ethereumjs-util": "^5.1.1",
--- a/packages/0x.js/scripts/postpublish.js
+++ b/packages/0x.js/scripts/postpublish.js
@@ -21,8 +21,9 @@ postpublish_utils.getLatestTagAndVersionAsync(subPackageName)
    })
    .then(function(release) {
        console.log('POSTPUBLISH: Release successful, generating docs...');
+        const jsonFilePath = __dirname + '/../' + postpublish_utils.generatedDocsDirectoryName + '/index.json';
        return execAsync(
-            'JSON_FILE_PATH=' +  __dirname + '/../docs/index.json PROJECT_DIR=' + __dirname + '/.. yarn docs:json',
+            'JSON_FILE_PATH=' + jsonFilePath + ' PROJECT_DIR=' + __dirname + '/.. yarn docs:json',
            {
                cwd,
            }
--- a/packages/0x.js/src/0x.ts
+++ b/packages/0x.js/src/0x.ts
@@ -1,34 +1,33 @@
-import * as _ from 'lodash';
+import {schemas, SchemaValidator} from '@0xproject/json-schemas';
+import {bigNumberConfigs, intervalUtils} from '@0xproject/utils';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
 import BigNumber from 'bignumber.js';
-import {SchemaValidator, schemas} from '@0xproject/json-schemas';
-import {bigNumberConfigs} from './bignumber_config';
 import * as ethUtil from 'ethereumjs-util';
-import {Web3Wrapper} from './web3_wrapper';
-import {constants} from './utils/constants';
-import {utils} from './utils/utils';
-import {signatureUtils} from './utils/signature_utils';
-import {assert} from './utils/assert';
-import {AbiDecoder} from './utils/abi_decoder';
-import {intervalUtils} from './utils/interval_utils';
+import * as _ from 'lodash';
+
 import {artifacts} from './artifacts';
+import {EtherTokenWrapper} from './contract_wrappers/ether_token_wrapper';
 import {ExchangeWrapper} from './contract_wrappers/exchange_wrapper';
 import {TokenRegistryWrapper} from './contract_wrappers/token_registry_wrapper';
-import {EtherTokenWrapper} from './contract_wrappers/ether_token_wrapper';
-import {TokenWrapper} from './contract_wrappers/token_wrapper';
 import {TokenTransferProxyWrapper} from './contract_wrappers/token_transfer_proxy_wrapper';
+import {TokenWrapper} from './contract_wrappers/token_wrapper';
 import {OrderStateWatcher} from './order_watcher/order_state_watcher';
-import {OrderStateUtils} from './utils/order_state_utils';
+import {zeroExConfigSchema} from './schemas/zero_ex_config_schema';
 import {
    ECSignature,
-    ZeroExError,
    Order,
    SignedOrder,
+    TransactionReceiptWithDecodedLogs,
    Web3Provider,
    ZeroExConfig,
-    OrderStateWatcherConfig,
-    TransactionReceiptWithDecodedLogs,
+    ZeroExError,
 } from './types';
-import {zeroExConfigSchema} from './schemas/zero_ex_config_schema';
+import {AbiDecoder} from './utils/abi_decoder';
+import {assert} from './utils/assert';
+import {constants} from './utils/constants';
+import {decorators} from './utils/decorators';
+import {signatureUtils} from './utils/signature_utils';
+import {utils} from './utils/utils';

 // Customize our BigNumber instances
 bigNumberConfigs.configure();
@@ -157,6 +156,7 @@ export class ZeroEx {
     * @param   order   An object that conforms to the Order or SignedOrder interface definitions.
     * @return  The resulting orderHash from hashing the supplied order.
     */
+    @decorators.syncZeroExErrorHandler
    public static getOrderHashHex(order: Order|SignedOrder): string {
        assert.doesConformToSchema('order', order, schemas.orderSchema);
        const orderHashHex = utils.getOrderHashHex(order);
@@ -169,56 +169,55 @@ export class ZeroEx {
     * @param   config      The configuration object. Look up the type for the description.
     * @return  An instance of the 0x.js ZeroEx class.
     */
-    constructor(provider: Web3Provider, config?: ZeroExConfig) {
+    constructor(provider: Web3Provider, config: ZeroExConfig) {
        assert.isWeb3Provider('provider', provider);
-        if (!_.isUndefined(config)) {
-            assert.doesConformToSchema('config', config, zeroExConfigSchema);
-        }
+        assert.doesConformToSchema('config', config, zeroExConfigSchema);
        const artifactJSONs = _.values(artifacts);
        const abiArrays = _.map(artifactJSONs, artifact => artifact.abi);
        this._abiDecoder = new AbiDecoder(abiArrays);
-        const gasPrice = _.isUndefined(config) ? undefined : config.gasPrice;
        const defaults = {
-            gasPrice,
+            gasPrice: config.gasPrice,
        };
        this._web3Wrapper = new Web3Wrapper(provider, defaults);
-        this.token = new TokenWrapper(
-            this._web3Wrapper,
-            this._abiDecoder,
-            this._getTokenTransferProxyAddressAsync.bind(this),
-        );
-        const exchageContractAddressIfExists = _.isUndefined(config) ? undefined : config.exchangeContractAddress;
-        this.exchange = new ExchangeWrapper(
-            this._web3Wrapper,
-            this._abiDecoder,
-            this.token,
-            exchageContractAddressIfExists,
-        );
        this.proxy = new TokenTransferProxyWrapper(
            this._web3Wrapper,
-            this._getTokenTransferProxyAddressAsync.bind(this),
+            config.networkId,
+            config.tokenTransferProxyContractAddress,
+        );
+        this.token = new TokenWrapper(
+            this._web3Wrapper,
+            config.networkId,
+            this._abiDecoder,
+            this.proxy,
+        );
+        this.exchange = new ExchangeWrapper(
+            this._web3Wrapper,
+            config.networkId,
+            this._abiDecoder,
+            this.token,
+            config.exchangeContractAddress,
+        );
+        this.tokenRegistry = new TokenRegistryWrapper(
+            this._web3Wrapper, config.networkId, config.tokenRegistryContractAddress,
+        );
+        this.etherToken = new EtherTokenWrapper(
+            this._web3Wrapper, config.networkId, this._abiDecoder, this.token,
        );
-        const tokenRegistryContractAddressIfExists = _.isUndefined(config) ?
-                                                     undefined :
-                                                     config.tokenRegistryContractAddress;
-        this.tokenRegistry = new TokenRegistryWrapper(this._web3Wrapper, tokenRegistryContractAddressIfExists);
-        const etherTokenContractAddressIfExists = _.isUndefined(config) ? undefined : config.etherTokenContractAddress;
-        this.etherToken = new EtherTokenWrapper(this._web3Wrapper, this.token, etherTokenContractAddressIfExists);
-        const orderWatcherConfig = _.isUndefined(config) ? undefined : config.orderWatcherConfig;
        this.orderStateWatcher = new OrderStateWatcher(
-            this._web3Wrapper, this._abiDecoder, this.token, this.exchange, orderWatcherConfig,
+            this._web3Wrapper, this._abiDecoder, this.token, this.exchange, config.orderWatcherConfig,
        );
    }
    /**
     * Sets a new web3 provider for 0x.js. Updating the provider will stop all
     * subscriptions so you will need to re-subscribe to all events relevant to your app after this call.
     * @param   provider    The Web3Provider you would like the 0x.js library to use from now on.
+     * @param   networkId   The id of the network your provider is connected to
     */
-    public async setProviderAsync(provider: Web3Provider) {
-        this._web3Wrapper.setProvider(provider);
-        await (this.exchange as any)._invalidateContractInstancesAsync();
+    public setProvider(provider: Web3Provider, networkId: number): void {
+        this._web3Wrapper.setProvider(provider, networkId);
+        (this.exchange as any)._invalidateContractInstances();
        (this.tokenRegistry as any)._invalidateContractInstance();
-        await (this.token as any)._invalidateContractInstancesAsync();
+        (this.token as any)._invalidateContractInstances();
        (this.proxy as any)._invalidateContractInstance();
        (this.etherToken as any)._invalidateContractInstance();
    }
--- a/packages/0x.js/src/artifacts.ts
+++ b/packages/0x.js/src/artifacts.ts
@@ -1,11 +1,15 @@
-import {Artifact} from './types';
-import * as TokenArtifact from './artifacts/Token.json';
-import * as ExchangeArtifact from './artifacts/Exchange.json';
+import * as DummyTokenArtifact from './artifacts/DummyToken.json';
 import * as EtherTokenArtifact from './artifacts/EtherToken.json';
+import * as ExchangeArtifact from './artifacts/Exchange.json';
+import * as TokenArtifact from './artifacts/Token.json';
 import * as TokenRegistryArtifact from './artifacts/TokenRegistry.json';
 import * as TokenTransferProxyArtifact from './artifacts/TokenTransferProxy.json';
+import * as ZRXArtifact from './artifacts/ZRX.json';
+import {Artifact} from './types';

 export const artifacts = {
+    ZRXArtifact: ZRXArtifact as any as Artifact,
+    DummyTokenArtifact: DummyTokenArtifact as any as Artifact,
    TokenArtifact: TokenArtifact as any as Artifact,
    ExchangeArtifact: ExchangeArtifact as any as Artifact,
    EtherTokenArtifact: EtherTokenArtifact as any as Artifact,
--- a/packages/0x.js/src/artifacts/DummyToken.json
+++ b/packages/0x.js/src/artifacts/DummyToken.json
@@ -0,0 +1,23 @@
+{
+    "contract_name": "DummyToken",
+    "abi":
+    [
+        {
+            "constant": false,
+            "inputs": [
+                {
+                    "name": "_target",
+                    "type": "address"
+                },
+                {
+                    "name": "_value",
+                    "type": "uint256"
+                }
+            ],
+            "name": "setBalance",
+            "outputs": [],
+            "payable": false,
+            "type": "function"
+        }
+    ]
+}
--- a/packages/0x.js/src/artifacts/EtherToken.json
+++ b/packages/0x.js/src/artifacts/EtherToken.json
@@ -231,215 +231,54 @@
      ],
      "name": "Approval",
      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "_owner",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "Deposit",
+      "type": "event"
+    },
+    {
+      "anonymous": false,
+      "inputs": [
+        {
+          "indexed": true,
+          "name": "_owner",
+          "type": "address"
+        },
+        {
+          "indexed": false,
+          "name": "_value",
+          "type": "uint256"
+        }
+      ],
+      "name": "Withdrawal",
+      "type": "event"
    }
  ],
-  "unlinked_binary": "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",
  "networks": {
    "1": {
-      "links": {},
-      "events": {
-        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef": {
-          "anonymous": false,
-          "inputs": [
-            {
-              "indexed": true,
-              "name": "_from",
-              "type": "address"
-            },
-            {
-              "indexed": true,
-              "name": "_to",
-              "type": "address"
-            },
-            {
-              "indexed": false,
-              "name": "_value",
-              "type": "uint256"
-            }
-          ],
-          "name": "Transfer",
-          "type": "event"
-        },
-        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925": {
-          "anonymous": false,
-          "inputs": [
-            {
-              "indexed": true,
-              "name": "_owner",
-              "type": "address"
-            },
-            {
-              "indexed": true,
-              "name": "_spender",
-              "type": "address"
-            },
-            {
-              "indexed": false,
-              "name": "_value",
-              "type": "uint256"
-            }
-          ],
-          "name": "Approval",
-          "type": "event"
-        }
-      },
-      "updated_at": 1502488087000,
-      "address": "0x2956356cd2a2bf3202f771f50d3d14a367b48070"
+      "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"
    },
    "3": {
-      "links": {},
-      "events": {
-        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef": {
-          "anonymous": false,
-          "inputs": [
-            {
-              "indexed": true,
-              "name": "_from",
-              "type": "address"
-            },
-            {
-              "indexed": true,
-              "name": "_to",
-              "type": "address"
-            },
-            {
-              "indexed": false,
-              "name": "_value",
-              "type": "uint256"
-            }
-          ],
-          "name": "Transfer",
-          "type": "event"
-        },
-        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925": {
-          "anonymous": false,
-          "inputs": [
-            {
-              "indexed": true,
-              "name": "_owner",
-              "type": "address"
-            },
-            {
-              "indexed": true,
-              "name": "_spender",
-              "type": "address"
-            },
-            {
-              "indexed": false,
-              "name": "_value",
-              "type": "uint256"
-            }
-          ],
-          "name": "Approval",
-          "type": "event"
-        }
-      },
-      "updated_at": 1506602007000,
      "address": "0xc00fd9820cd2898cc4c054b7bf142de637ad129a"
    },
    "42": {
-      "links": {},
-      "events": {
-        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef": {
-          "anonymous": false,
-          "inputs": [
-            {
-              "indexed": true,
-              "name": "_from",
-              "type": "address"
-            },
-            {
-              "indexed": true,
-              "name": "_to",
-              "type": "address"
-            },
-            {
-              "indexed": false,
-              "name": "_value",
-              "type": "uint256"
-            }
-          ],
-          "name": "Transfer",
-          "type": "event"
-        },
-        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925": {
-          "anonymous": false,
-          "inputs": [
-            {
-              "indexed": true,
-              "name": "_owner",
-              "type": "address"
-            },
-            {
-              "indexed": true,
-              "name": "_spender",
-              "type": "address"
-            },
-            {
-              "indexed": false,
-              "name": "_value",
-              "type": "uint256"
-            }
-          ],
-          "name": "Approval",
-          "type": "event"
-        }
-      },
-      "updated_at": 1502391794392,
-      "address": "0x05d090b51c40b020eab3bfcb6a2dff130df22e9c"
+      "address": "0x653e49e301e508a13237c0ddc98ae7d4cd2667a1"
    },
    "50": {
-      "links": {},
-      "events": {
-        "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef": {
-          "anonymous": false,
-          "inputs": [
-            {
-              "indexed": true,
-              "name": "_from",
-              "type": "address"
-            },
-            {
-              "indexed": true,
-              "name": "_to",
-              "type": "address"
-            },
-            {
-              "indexed": false,
-              "name": "_value",
-              "type": "uint256"
-            }
-          ],
-          "name": "Transfer",
-          "type": "event"
-        },
-        "0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925": {
-          "anonymous": false,
-          "inputs": [
-            {
-              "indexed": true,
-              "name": "_owner",
-              "type": "address"
-            },
-            {
-              "indexed": true,
-              "name": "_spender",
-              "type": "address"
-            },
-            {
-              "indexed": false,
-              "name": "_value",
-              "type": "uint256"
-            }
-          ],
-          "name": "Approval",
-          "type": "event"
-        }
-      },
-      "updated_at": 1503318938233,
-      "address": "0x48bacb9266a570d521063ef5dd96e61686dbe788"
+      "address": "0x871dd7c2b4b25e1aa18728e9d5f2af4c4e431f5c"
    }
-  },
-  "schema_version": "0.0.5",
-  "updated_at": 1503318938233
+  }
 }
--- a/packages/0x.js/src/artifacts/Exchange.json
+++ b/packages/0x.js/src/artifacts/Exchange.json
--- a/packages/0x.js/src/artifacts/Token.json
+++ b/packages/0x.js/src/artifacts/Token.json
@@ -168,9 +168,5 @@
      "name": "Approval",
      "type": "event"
    }
-  ],
-  "unlinked_binary": "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",
-  "networks": {},
-  "schema_version": "0.0.5",
-  "updated_at": 1503317882695
-}
+  ]
+}
--- a/packages/0x.js/src/artifacts/TokenRegistry.json
+++ b/packages/0x.js/src/artifacts/TokenRegistry.json
--- a/packages/0x.js/src/artifacts/TokenTransferProxy.json
+++ b/packages/0x.js/src/artifacts/TokenTransferProxy.json
@@ -167,8 +167,18 @@
      "type": "event"
    }
  ],
-  "unlinked_binary": "0x60606040525b60008054600160a060020a03191633600160a060020a03161790555b5b6106e6806100316000396000f300606060405236156100725763ffffffff60e060020a60003504166315dacbea811461007457806342f1181e146100b3578063494503d4146100d157806370712939146101005780638da5cb5b1461011e578063b91816111461014a578063d39de6e91461017a578063f2fde38b146101e5575bfe5b341561007c57fe5b61009f600160a060020a0360043581169060243581169060443516606435610203565b604080519115158252519081900360200190f35b34156100bb57fe5b6100cf600160a060020a03600435166102ae565b005b34156100d957fe5b6100e4600435610390565b60408051600160a060020a039092168252519081900360200190f35b341561010857fe5b6100cf600160a060020a03600435166103c2565b005b341561012657fe5b6100e461055a565b60408051600160a060020a039092168252519081900360200190f35b341561015257fe5b61009f600160a060020a0360043516610569565b604080519115158252519081900360200190f35b341561018257fe5b61018a61057e565b60408051602080825283518183015283519192839290830191858101910280838382156101d2575b8051825260208311156101d257601f1990920191602091820191016101b2565b5050509050019250505060405180910390f35b34156101ed57fe5b6100cf600160a060020a03600435166105e7565b005b600160a060020a03331660009081526001602052604081205460ff16151561022b5760006000fd5b6040805160006020918201819052825160e060020a6323b872dd028152600160a060020a0388811660048301528781166024830152604482018790529351938916936323b872dd9360648084019491938390030190829087803b151561028d57fe5b6102c65a03f1151561029b57fe5b5050604051519150505b5b949350505050565b60005433600160a060020a039081169116146102ca5760006000fd5b600160a060020a038116600090815260016020526040902054819060ff16156102f35760006000fd5b600160a060020a0382166000908152600160208190526040909120805460ff191682179055600280549091810161032a8382610633565b916000526020600020900160005b81546101009190910a600160a060020a0381810219909216868316918202179092556040513390911692507f94bb87f4c15c4587ff559a7584006fa01ddf9299359be6b512b94527aa961aca90600090a35b5b505b50565b600280548290811061039e57fe5b906000526020600020900160005b915054906101000a9004600160a060020a031681565b6000805433600160a060020a039081169116146103df5760006000fd5b600160a060020a038216600090815260016020526040902054829060ff1615156104095760006000fd5b600160a060020a0383166000908152600160205260408120805460ff1916905591505b6002548210156105195782600160a060020a031660028381548110151561044f57fe5b906000526020600020900160005b9054906101000a9004600160a060020a0316600160a060020a0316141561050d5760028054600019810190811061049057fe5b906000526020600020900160005b9054906101000a9004600160a060020a03166002838154811015156104bf57fe5b906000526020600020900160005b6101000a815481600160a060020a030219169083600160a060020a0316021790555060016002818180549050039150816105079190610633565b50610519565b5b60019091019061042c565b604051600160a060020a0333811691908516907ff5b347a1e40749dd050f5f07fbdbeb7e3efa9756903044dd29401fd1d4bb4a1c90600090a35b5b505b5050565b600054600160a060020a031681565b60016020526000908152604090205460ff1681565b610586610687565b60028054806020026020016040519081016040528092919081815260200182805480156105dc57602002820191906000526020600020905b8154600160a060020a031681526001909101906020018083116105be575b505050505090505b90565b60005433600160a060020a039081169116146106035760006000fd5b600160a060020a0381161561038d5760008054600160a060020a031916600160a060020a0383161790555b5b5b50565b81548183558181151161055357600083815260209020610553918101908301610699565b5b505050565b81548183558181151161055357600083815260209020610553918101908301610699565b5b505050565b60408051602081019091526000815290565b6105e491905b808211156106b3576000815560010161069f565b5090565b905600a165627a7a72305820d2924957bb88a128789172e164d874fe5445218fc2dde2f5eb265839a1f341a20029",
-  "networks": {},
-  "schema_version": "0.0.5",
-  "updated_at": 1503318938227
+  "networks": {
+      "1": {
+        "address": "0x8da0d80f5007ef1e431dd2127178d224e32c2ef4"
+      },
+      "3": {
+        "address": "0x4e9aad8184de8833365fea970cd9149372fdf1e6"
+      },
+      "42": {
+        "address": "0x087eed4bc1ee3de49befbd66c662b434b15d49d4"
+      },
+      "50": {
+        "address": "0x1dc4c1cefef38a777b15aa20260a54e584b16c48"
+      }
+  }
 }
--- a/packages/0x.js/src/artifacts/ZRX.json
+++ b/packages/0x.js/src/artifacts/ZRX.json
@@ -0,0 +1,17 @@
+{
+  "contract_name": "ZRX",
+  "networks": {
+    "1": {
+      "address": "0xe41d2489571d322189246dafa5ebde1f4699f498"
+    },
+    "3": {
+      "address": "0xa8e9fa8f91e5ae138c74648c9c304f1c75003a8d"
+    },
+    "42": {
+      "address": "0x6ff6c0ff1d68b964901f986d4c9fa3ac68346570"
+    },
+    "50": {
+      "address": "0x1d7022f5b17d2f8b695918fb48fa1089c9f85401"
+    }
+  }
+}
--- a/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
+++ b/packages/0x.js/src/contract_wrappers/contract_wrapper.ts
@@ -1,47 +1,56 @@
+import {intervalUtils} from '@0xproject/utils';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
+import {Block, BlockAndLogStreamer} from 'ethereumjs-blockstream';
 import * as _ from 'lodash';
 import * as Web3 from 'web3';
-import {BlockAndLogStreamer, Block} from 'ethereumjs-blockstream';
-import {Web3Wrapper} from '../web3_wrapper';
-import {AbiDecoder} from '../utils/abi_decoder';
+
 import {
-    ZeroExError,
-    InternalZeroExError,
    Artifact,
+    BlockParamLiteral,
+    BlockRange,
+    ContractEventArgs,
+    ContractEvents,
+    EventCallback,
+    IndexedFilterValues,
+    InternalZeroExError,
    LogWithDecodedArgs,
    RawLog,
-    ContractEvents,
-    SubscriptionOpts,
-    IndexedFilterValues,
-    EventCallback,
-    BlockParamLiteral,
-    ContractEventArgs,
+    ZeroExError,
 } from '../types';
+import {AbiDecoder} from '../utils/abi_decoder';
 import {constants} from '../utils/constants';
-import {intervalUtils} from '../utils/interval_utils';
 import {filterUtils} from '../utils/filter_utils';

+const CONTRACT_NAME_TO_NOT_FOUND_ERROR: {[contractName: string]: ZeroExError} = {
+    ZRX: ZeroExError.ZRXContractDoesNotExist,
+    EtherToken: ZeroExError.EtherTokenContractDoesNotExist,
+    Token: ZeroExError.TokenContractDoesNotExist,
+    TokenRegistry: ZeroExError.TokenRegistryContractDoesNotExist,
+    TokenTransferProxy: ZeroExError.TokenTransferProxyContractDoesNotExist,
+    Exchange: ZeroExError.ExchangeContractDoesNotExist,
+};
+
 export class ContractWrapper {
    protected _web3Wrapper: Web3Wrapper;
+    private _networkId: number;
    private _abiDecoder?: AbiDecoder;
-    private _blockAndLogStreamer: BlockAndLogStreamer|undefined;
+    private _blockAndLogStreamerIfExists: BlockAndLogStreamer|undefined;
    private _blockAndLogStreamInterval: NodeJS.Timer;
    private _filters: {[filterToken: string]: Web3.FilterObject};
    private _filterCallbacks: {[filterToken: string]: EventCallback<ContractEventArgs>};
    private _onLogAddedSubscriptionToken: string|undefined;
    private _onLogRemovedSubscriptionToken: string|undefined;
-    constructor(web3Wrapper: Web3Wrapper, abiDecoder?: AbiDecoder) {
+    constructor(web3Wrapper: Web3Wrapper, networkId: number, abiDecoder?: AbiDecoder) {
        this._web3Wrapper = web3Wrapper;
+        this._networkId = networkId;
        this._abiDecoder = abiDecoder;
        this._filters = {};
        this._filterCallbacks = {};
-        this._blockAndLogStreamer = undefined;
+        this._blockAndLogStreamerIfExists = undefined;
        this._onLogAddedSubscriptionToken = undefined;
        this._onLogRemovedSubscriptionToken = undefined;
    }
-    /**
-     * Cancels all existing subscriptions
-     */
-    public unsubscribeAll(): void {
+    protected unsubscribeAll(): void {
        const filterTokens = _.keys(this._filterCallbacks);
        _.each(filterTokens, filterToken => {
            this._unsubscribe(filterToken);
@@ -65,7 +74,7 @@ export class ContractWrapper {
        address: string, eventName: ContractEvents, indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi,
        callback: EventCallback<ArgsType>): string {
        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi);
-        if (_.isUndefined(this._blockAndLogStreamer)) {
+        if (_.isUndefined(this._blockAndLogStreamerIfExists)) {
            this._startBlockAndLogStream();
        }
        const filterToken = filterUtils.generateUUID();
@@ -74,9 +83,9 @@ export class ContractWrapper {
        return filterToken;
    }
    protected async _getLogsAsync<ArgsType extends ContractEventArgs>(
-        address: string, eventName: ContractEvents, subscriptionOpts: SubscriptionOpts,
+        address: string, eventName: ContractEvents, blockRange: BlockRange,
        indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
-        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi, subscriptionOpts);
+        const filter = filterUtils.getFilter(address, eventName, indexFilterValues, abi, blockRange);
        const logs = await this._web3Wrapper.getLogsAsync(filter);
        const logsWithDecodedArguments = _.map(logs, this._tryToDecodeLogOrNoop.bind(this));
        return logsWithDecodedArguments;
@@ -89,58 +98,88 @@ export class ContractWrapper {
        const logWithDecodedArgs = this._abiDecoder.tryToDecodeLogOrNoop(log);
        return logWithDecodedArgs;
    }
-    protected async _instantiateContractIfExistsAsync<ContractType extends Web3.ContractInstance>(
-        artifact: Artifact, addressIfExists?: string): Promise<ContractType> {
-        const contractInstance =
-            await this._web3Wrapper.getContractInstanceFromArtifactAsync<ContractType>(artifact, addressIfExists);
+    protected async _instantiateContractIfExistsAsync(
+        artifact: Artifact, addressIfExists?: string,
+    ): Promise<Web3.ContractInstance> {
+        let contractAddress: string;
+        if (_.isUndefined(addressIfExists)) {
+            if (_.isUndefined(artifact.networks[this._networkId])) {
+                throw new Error(ZeroExError.ContractNotDeployedOnNetwork);
+            }
+            contractAddress = artifact.networks[this._networkId].address.toLowerCase();
+        } else {
+            contractAddress = addressIfExists;
+        }
+        const doesContractExist = await this._web3Wrapper.doesContractExistAtAddressAsync(contractAddress);
+        if (!doesContractExist) {
+            throw new Error(CONTRACT_NAME_TO_NOT_FOUND_ERROR[artifact.contract_name]);
+        }
+        const contractInstance = this._web3Wrapper.getContractInstance(
+            artifact.abi, contractAddress,
+        );
        return contractInstance;
    }
-    private _onLogStateChanged<ArgsType extends ContractEventArgs>(removed: boolean, log: Web3.LogEntry): void {
+    protected _getContractAddress(artifact: Artifact, addressIfExists?: string): string {
+        if (_.isUndefined(addressIfExists)) {
+            const contractAddress = artifact.networks[this._networkId].address;
+            if (_.isUndefined(contractAddress)) {
+                throw new Error(ZeroExError.ExchangeContractDoesNotExist);
+            }
+            return contractAddress;
+        } else {
+            return addressIfExists;
+        }
+    }
+    private _onLogStateChanged<ArgsType extends ContractEventArgs>(isRemoved: boolean, log: Web3.LogEntry): void {
        _.forEach(this._filters, (filter: Web3.FilterObject, filterToken: string) => {
            if (filterUtils.matchesFilter(log, filter)) {
                const decodedLog = this._tryToDecodeLogOrNoop(log) as LogWithDecodedArgs<ArgsType>;
                const logEvent = {
-                    ...decodedLog,
-                    removed,
+                    log: decodedLog,
+                    isRemoved,
                };
                this._filterCallbacks[filterToken](null, logEvent);
            }
        });
    }
    private _startBlockAndLogStream(): void {
-        this._blockAndLogStreamer = new BlockAndLogStreamer(
+        if (!_.isUndefined(this._blockAndLogStreamerIfExists)) {
+            throw new Error(ZeroExError.SubscriptionAlreadyPresent);
+        }
+        this._blockAndLogStreamerIfExists = new BlockAndLogStreamer(
            this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper),
            this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper),
        );
        const catchAllLogFilter = {};
-        this._blockAndLogStreamer.addLogFilter(catchAllLogFilter);
+        this._blockAndLogStreamerIfExists.addLogFilter(catchAllLogFilter);
        this._blockAndLogStreamInterval = intervalUtils.setAsyncExcludingInterval(
            this._reconcileBlockAsync.bind(this), constants.DEFAULT_BLOCK_POLLING_INTERVAL,
        );
-        let removed = false;
-        this._onLogAddedSubscriptionToken = this._blockAndLogStreamer.subscribeToOnLogAdded(
-            this._onLogStateChanged.bind(this, removed),
+        let isRemoved = false;
+        this._onLogAddedSubscriptionToken = this._blockAndLogStreamerIfExists.subscribeToOnLogAdded(
+            this._onLogStateChanged.bind(this, isRemoved),
        );
-        removed = true;
-        this._onLogRemovedSubscriptionToken = this._blockAndLogStreamer.subscribeToOnLogRemoved(
-            this._onLogStateChanged.bind(this, removed),
+        isRemoved = true;
+        this._onLogRemovedSubscriptionToken = this._blockAndLogStreamerIfExists.subscribeToOnLogRemoved(
+            this._onLogStateChanged.bind(this, isRemoved),
        );
    }
    private _stopBlockAndLogStream(): void {
-        (this._blockAndLogStreamer as BlockAndLogStreamer).unsubscribeFromOnLogAdded(
-            this._onLogAddedSubscriptionToken as string);
-        (this._blockAndLogStreamer as BlockAndLogStreamer).unsubscribeFromOnLogRemoved(
-            this._onLogRemovedSubscriptionToken as string);
+        if (_.isUndefined(this._blockAndLogStreamerIfExists)) {
+            throw new Error(ZeroExError.SubscriptionNotFound);
+        }
+        this._blockAndLogStreamerIfExists.unsubscribeFromOnLogAdded(this._onLogAddedSubscriptionToken as string);
+        this._blockAndLogStreamerIfExists.unsubscribeFromOnLogRemoved(this._onLogRemovedSubscriptionToken as string);
        intervalUtils.clearAsyncExcludingInterval(this._blockAndLogStreamInterval);
-        delete this._blockAndLogStreamer;
+        delete this._blockAndLogStreamerIfExists;
    }
    private async _reconcileBlockAsync(): Promise<void> {
        try {
            const latestBlock = await this._web3Wrapper.getBlockAsync(BlockParamLiteral.Latest);
            // We need to coerce to Block type cause Web3.Block includes types for mempool blocks
-            if (!_.isUndefined(this._blockAndLogStreamer)) {
+            if (!_.isUndefined(this._blockAndLogStreamerIfExists)) {
                // If we clear the interval while fetching the block - this._blockAndLogStreamer will be undefined
-                this._blockAndLogStreamer.reconcileNewBlock(latestBlock as any as Block);
+                await this._blockAndLogStreamerIfExists.reconcileNewBlock(latestBlock as any as Block);
            }
        } catch (err) {
            const filterTokens = _.keys(this._filterCallbacks);
--- a/packages/0x.js/src/contract_wrappers/ether_token_wrapper.ts
+++ b/packages/0x.js/src/contract_wrappers/ether_token_wrapper.ts
@@ -1,87 +1,161 @@
-import * as _ from 'lodash';
+import {schemas} from '@0xproject/json-schemas';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
 import BigNumber from 'bignumber.js';
-import {Web3Wrapper} from '../web3_wrapper';
-import {ContractWrapper} from './contract_wrapper';
-import {TokenWrapper} from './token_wrapper';
-import {EtherTokenContract, ZeroExError} from '../types';
-import {assert} from '../utils/assert';
+import * as _ from 'lodash';
+
 import {artifacts} from '../artifacts';
+import {
+    BlockRange,
+    EtherTokenContractEventArgs,
+    EtherTokenEvents,
+    EventCallback,
+    IndexedFilterValues,
+    LogWithDecodedArgs,
+    TransactionOpts,
+    ZeroExError,
+} from '../types';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {assert} from '../utils/assert';
+
+import {ContractWrapper} from './contract_wrapper';
+import {EtherTokenContract} from './generated/ether_token';
+import {TokenWrapper} from './token_wrapper';

 /**
 * This class includes all the functionality related to interacting with a wrapped Ether ERC20 token contract.
 * The caller can convert ETH into the equivalent number of wrapped ETH ERC20 tokens and back.
 */
 export class EtherTokenWrapper extends ContractWrapper {
-    private _etherTokenContractIfExists?: EtherTokenContract;
+    private _etherTokenContractsByAddress: {[address: string]: EtherTokenContract} = {};
    private _tokenWrapper: TokenWrapper;
-    private _contractAddressIfExists?: string;
-    constructor(web3Wrapper: Web3Wrapper, tokenWrapper: TokenWrapper, contractAddressIfExists?: string) {
-        super(web3Wrapper);
+    constructor(web3Wrapper: Web3Wrapper, networkId: number, abiDecoder: AbiDecoder, tokenWrapper: TokenWrapper) {
+        super(web3Wrapper, networkId, abiDecoder);
        this._tokenWrapper = tokenWrapper;
-        this._contractAddressIfExists = contractAddressIfExists;
    }
    /**
     * Deposit ETH into the Wrapped ETH smart contract and issues the equivalent number of wrapped ETH tokens
     * to the depositor address. These wrapped ETH tokens can be used in 0x trades and are redeemable for 1-to-1
     * for ETH.
-     * @param   amountInWei      Amount of ETH in Wei the caller wishes to deposit.
-     * @param   depositor   The hex encoded user Ethereum address that would like to make the deposit.
+     * @param   etherTokenAddress   EtherToken address you wish to deposit into.
+     * @param   amountInWei         Amount of ETH in Wei the caller wishes to deposit.
+     * @param   depositor           The hex encoded user Ethereum address that would like to make the deposit.
+     * @param   txOpts              Transaction parameters.
     * @return Transaction hash.
     */
-    public async depositAsync(amountInWei: BigNumber, depositor: string): Promise<string> {
+    public async depositAsync(
+        etherTokenAddress: string, amountInWei: BigNumber, depositor: string, txOpts: TransactionOpts = {},
+    ): Promise<string> {
        assert.isValidBaseUnitAmount('amountInWei', amountInWei);
        await assert.isSenderAddressAsync('depositor', depositor, this._web3Wrapper);

        const ethBalanceInWei = await this._web3Wrapper.getBalanceInWeiAsync(depositor);
        assert.assert(ethBalanceInWei.gte(amountInWei), ZeroExError.InsufficientEthBalanceForDeposit);

-        const wethContract = await this._getEtherTokenContractAsync();
+        const wethContract = await this._getEtherTokenContractAsync(etherTokenAddress);
        const txHash = await wethContract.deposit.sendTransactionAsync({
            from: depositor,
            value: amountInWei,
+            gas: txOpts.gasLimit,
+            gasPrice: txOpts.gasPrice,
        });
        return txHash;
    }
    /**
     * Withdraw ETH to the withdrawer's address from the wrapped ETH smart contract in exchange for the
     * equivalent number of wrapped ETH tokens.
+     * @param   etherTokenAddress   EtherToken address you wish to withdraw from.
     * @param   amountInWei  Amount of ETH in Wei the caller wishes to withdraw.
     * @param   withdrawer   The hex encoded user Ethereum address that would like to make the withdrawl.
+     * @param   txOpts       Transaction parameters.
     * @return Transaction hash.
     */
-    public async withdrawAsync(amountInWei: BigNumber, withdrawer: string): Promise<string> {
+    public async withdrawAsync(
+        etherTokenAddress: string, amountInWei: BigNumber, withdrawer: string, txOpts: TransactionOpts = {},
+    ): Promise<string> {
        assert.isValidBaseUnitAmount('amountInWei', amountInWei);
        await assert.isSenderAddressAsync('withdrawer', withdrawer, this._web3Wrapper);

-        const wethContractAddress = await this.getContractAddressAsync();
-        const WETHBalanceInBaseUnits = await this._tokenWrapper.getBalanceAsync(wethContractAddress, withdrawer);
+        const WETHBalanceInBaseUnits = await this._tokenWrapper.getBalanceAsync(etherTokenAddress, withdrawer);
        assert.assert(WETHBalanceInBaseUnits.gte(amountInWei), ZeroExError.InsufficientWEthBalanceForWithdrawal);

-        const wethContract = await this._getEtherTokenContractAsync();
+        const wethContract = await this._getEtherTokenContractAsync(etherTokenAddress);
        const txHash = await wethContract.withdraw.sendTransactionAsync(amountInWei, {
            from: withdrawer,
+            gas: txOpts.gasLimit,
+            gasPrice: txOpts.gasPrice,
        });
        return txHash;
    }
    /**
-     * Retrieves the Wrapped Ether token contract address
-     * @return  The Wrapped Ether token contract address
+     * Gets historical logs without creating a subscription
+     * @param   etherTokenAddress   An address of the ether token that emmited the logs.
+     * @param   eventName           The ether token contract event you would like to subscribe to.
+     * @param   blockRange          Block range to get logs from.
+     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
+     *                              the value is the value you are interested in. E.g `{_owner: aUserAddressHex}`
+     * @return  Array of logs that match the parameters
     */
-    public async getContractAddressAsync(): Promise<string> {
-        const wethContract = await this._getEtherTokenContractAsync();
-        return wethContract.address;
+    public async getLogsAsync<ArgsType extends EtherTokenContractEventArgs>(
+        etherTokenAddress: string, eventName: EtherTokenEvents, blockRange: BlockRange,
+        indexFilterValues: IndexedFilterValues): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
+        assert.isETHAddressHex('etherTokenAddress', etherTokenAddress);
+        assert.doesBelongToStringEnum('eventName', eventName, EtherTokenEvents);
+        assert.doesConformToSchema('blockRange', blockRange, schemas.blockRangeSchema);
+        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
+        const logs = await this._getLogsAsync<ArgsType>(
+            etherTokenAddress, eventName, blockRange, indexFilterValues, artifacts.EtherTokenArtifact.abi,
+        );
+        return logs;
+    }
+    /**
+     * Subscribe to an event type emitted by the Token contract.
+     * @param   etherTokenAddress   The hex encoded address where the ether token is deployed.
+     * @param   eventName           The ether token contract event you would like to subscribe to.
+     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
+     *                              the value is the value you are interested in. E.g `{_owner: aUserAddressHex}`
+     * @param   callback            Callback that gets called when a log is added/removed
+     * @return Subscription token used later to unsubscribe
+     */
+    public subscribe<ArgsType extends EtherTokenContractEventArgs>(
+        etherTokenAddress: string, eventName: EtherTokenEvents, indexFilterValues: IndexedFilterValues,
+        callback: EventCallback<ArgsType>): string {
+        assert.isETHAddressHex('etherTokenAddress', etherTokenAddress);
+        assert.doesBelongToStringEnum('eventName', eventName, EtherTokenEvents);
+        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
+        assert.isFunction('callback', callback);
+        const subscriptionToken = this._subscribe<ArgsType>(
+            etherTokenAddress, eventName, indexFilterValues, artifacts.EtherTokenArtifact.abi, callback,
+        );
+        return subscriptionToken;
+    }
+    /**
+     * Cancel a subscription
+     * @param   subscriptionToken Subscription token returned by `subscribe()`
+     */
+    public unsubscribe(subscriptionToken: string): void {
+        this._unsubscribe(subscriptionToken);
+    }
+    /**
+     * Cancels all existing subscriptions
+     */
+    public unsubscribeAll(): void {
+        super.unsubscribeAll();
    }
    private _invalidateContractInstance(): void {
-        delete this._etherTokenContractIfExists;
+        this.unsubscribeAll();
+        this._etherTokenContractsByAddress = {};
    }
-    private async _getEtherTokenContractAsync(): Promise<EtherTokenContract> {
-        if (!_.isUndefined(this._etherTokenContractIfExists)) {
-            return this._etherTokenContractIfExists;
+    private async _getEtherTokenContractAsync(etherTokenAddress: string): Promise<EtherTokenContract> {
+        let etherTokenContract = this._etherTokenContractsByAddress[etherTokenAddress];
+        if (!_.isUndefined(etherTokenContract)) {
+            return etherTokenContract;
        }
-        const contractInstance = await this._instantiateContractIfExistsAsync<EtherTokenContract>(
-            artifacts.EtherTokenArtifact, this._contractAddressIfExists,
+        const web3ContractInstance = await this._instantiateContractIfExistsAsync(
+            artifacts.EtherTokenArtifact, etherTokenAddress,
        );
-        this._etherTokenContractIfExists = contractInstance as EtherTokenContract;
-        return this._etherTokenContractIfExists;
+        const contractInstance = new EtherTokenContract(web3ContractInstance, this._web3Wrapper.getContractDefaults());
+        etherTokenContract = contractInstance;
+        this._etherTokenContractsByAddress[etherTokenAddress] = etherTokenContract;
+        return etherTokenContract;
    }
 }
--- a/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
+++ b/packages/0x.js/src/contract_wrappers/exchange_wrapper.ts
@@ -1,44 +1,43 @@
+import {schemas} from '@0xproject/json-schemas';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
+import BigNumber from 'bignumber.js';
 import * as _ from 'lodash';
 import * as Web3 from 'web3';
-import BigNumber from 'bignumber.js';
-import {schemas} from '@0xproject/json-schemas';
-import {Web3Wrapper} from '../web3_wrapper';
+
+import {artifacts} from '../artifacts';
 import {
+    BlockParamLiteral,
+    BlockRange,
+    DecodedLogArgs,
    ECSignature,
-    ExchangeContract,
+    EventCallback,
    ExchangeContractErrCodes,
    ExchangeContractErrs,
-    ZeroExError,
-    OrderValues,
-    OrderAddresses,
-    Order,
-    SignedOrder,
+    ExchangeContractEventArgs,
    ExchangeEvents,
-    SubscriptionOpts,
    IndexedFilterValues,
-    OrderCancellationRequest,
-    OrderFillRequest,
    LogErrorContractEventArgs,
-    LogFillContractEventArgs,
-    LogCancelContractEventArgs,
    LogWithDecodedArgs,
    MethodOpts,
-    ValidateOrderFillableOpts,
+    Order,
+    OrderAddresses,
+    OrderCancellationRequest,
+    OrderFillRequest,
    OrderTransactionOpts,
-    RawLog,
-    EventCallback,
-    ExchangeContractEventArgs,
-    DecodedLogArgs,
+    OrderValues,
+    SignedOrder,
+    ValidateOrderFillableOpts,
 } from '../types';
-import {assert} from '../utils/assert';
-import {utils} from '../utils/utils';
-import {OrderValidationUtils} from '../utils/order_validation_utils';
-import {ContractWrapper} from './contract_wrapper';
-import {TokenWrapper} from './token_wrapper';
-import {decorators} from '../utils/decorators';
 import {AbiDecoder} from '../utils/abi_decoder';
+import {assert} from '../utils/assert';
+import {decorators} from '../utils/decorators';
 import {ExchangeTransferSimulator} from '../utils/exchange_transfer_simulator';
-import {artifacts} from '../artifacts';
+import {OrderValidationUtils} from '../utils/order_validation_utils';
+import {utils} from '../utils/utils';
+
+import {ContractWrapper} from './contract_wrapper';
+import {ExchangeContract} from './generated/exchange';
+import {TokenWrapper} from './token_wrapper';

 const SHOULD_VALIDATE_BY_DEFAULT = true;

@@ -63,6 +62,7 @@ export class ExchangeWrapper extends ContractWrapper {
        [ExchangeContractErrCodes.ERROR_FILL_BALANCE_ALLOWANCE]: ExchangeContractErrs.FillBalanceAllowanceError,
    };
    private _contractAddressIfExists?: string;
+    private _zrxContractAddressIfExists?: string;
    private static _getOrderAddressesAndValues(order: Order): [OrderAddresses, OrderValues] {
        const orderAddresses: OrderAddresses = [
            order.maker,
@@ -81,11 +81,11 @@ export class ExchangeWrapper extends ContractWrapper {
        ];
        return [orderAddresses, orderValues];
    }
-    constructor(web3Wrapper: Web3Wrapper, abiDecoder: AbiDecoder,
+    constructor(web3Wrapper: Web3Wrapper, networkId: number, abiDecoder: AbiDecoder,
                tokenWrapper: TokenWrapper, contractAddressIfExists?: string) {
-        super(web3Wrapper, abiDecoder);
+        super(web3Wrapper, networkId, abiDecoder);
        this._tokenWrapper = tokenWrapper;
-        this._orderValidationUtils = new OrderValidationUtils(tokenWrapper, this);
+        this._orderValidationUtils = new OrderValidationUtils(this);
        this._contractAddressIfExists = contractAddressIfExists;
    }
    /**
@@ -162,41 +162,29 @@ export class ExchangeWrapper extends ContractWrapper {
     * @param   orderTransactionOpts                        Optional arguments this method accepts.
     * @return  Transaction hash.
     */
-    @decorators.contractCallErrorHandler
+    @decorators.asyncZeroExErrorHandler
    public async fillOrderAsync(signedOrder: SignedOrder, fillTakerTokenAmount: BigNumber,
                                shouldThrowOnInsufficientBalanceOrAllowance: boolean,
                                takerAddress: string,
-                                orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+                                orderTransactionOpts: OrderTransactionOpts = {}): Promise<string> {
        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);

        const exchangeInstance = await this._getExchangeContractAsync();
-        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
-            SHOULD_VALIDATE_BY_DEFAULT :
-            orderTransactionOpts.shouldValidate;
+        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate) ?
+                               SHOULD_VALIDATE_BY_DEFAULT :
+                               orderTransactionOpts.shouldValidate;
        if (shouldValidate) {
-            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            const zrxTokenAddress = this.getZRXTokenAddress();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
            await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
                exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
        }

        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(signedOrder);

-        const gas = await exchangeInstance.fillOrder.estimateGasAsync(
-            orderAddresses,
-            orderValues,
-            fillTakerTokenAmount,
-            shouldThrowOnInsufficientBalanceOrAllowance,
-            signedOrder.ecSignature.v,
-            signedOrder.ecSignature.r,
-            signedOrder.ecSignature.s,
-            {
-                from: takerAddress,
-            },
-        );
        const txHash: string = await exchangeInstance.fillOrder.sendTransactionAsync(
            orderAddresses,
            orderValues,
@@ -207,7 +195,8 @@ export class ExchangeWrapper extends ContractWrapper {
            signedOrder.ecSignature.s,
            {
                from: takerAddress,
-                gas,
+                gas: orderTransactionOpts.gasLimit,
+                gasPrice: orderTransactionOpts.gasPrice,
            },
        );
        return txHash;
@@ -229,11 +218,11 @@ export class ExchangeWrapper extends ContractWrapper {
     * @param   orderTransactionOpts                        Optional arguments this method accepts.
     * @return  Transaction hash.
     */
-    @decorators.contractCallErrorHandler
+    @decorators.asyncZeroExErrorHandler
    public async fillOrdersUpToAsync(signedOrders: SignedOrder[], fillTakerTokenAmount: BigNumber,
                                     shouldThrowOnInsufficientBalanceOrAllowance: boolean,
                                     takerAddress: string,
-                                     orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+                                     orderTransactionOpts: OrderTransactionOpts = {}): Promise<string> {
        assert.doesConformToSchema('signedOrders', signedOrders, schemas.signedOrdersSchema);
        const takerTokenAddresses = _.map(signedOrders, signedOrder => signedOrder.takerTokenAddress);
        assert.hasAtMostOneUniqueValue(takerTokenAddresses,
@@ -245,12 +234,12 @@ export class ExchangeWrapper extends ContractWrapper {
        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);

-        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
-            SHOULD_VALIDATE_BY_DEFAULT :
-            orderTransactionOpts.shouldValidate;
+        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate) ?
+                               SHOULD_VALIDATE_BY_DEFAULT :
+                               orderTransactionOpts.shouldValidate;
        if (shouldValidate) {
-            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            const zrxTokenAddress = this.getZRXTokenAddress();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
            for (const signedOrder of signedOrders) {
                await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
                    exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
@@ -275,18 +264,6 @@ export class ExchangeWrapper extends ContractWrapper {
        );

        const exchangeInstance = await this._getExchangeContractAsync();
-        const gas = await exchangeInstance.fillOrdersUpTo.estimateGasAsync(
-            orderAddressesArray,
-            orderValuesArray,
-            fillTakerTokenAmount,
-            shouldThrowOnInsufficientBalanceOrAllowance,
-            vArray,
-            rArray,
-            sArray,
-            {
-                from: takerAddress,
-            },
-        );
        const txHash = await exchangeInstance.fillOrdersUpTo.sendTransactionAsync(
            orderAddressesArray,
            orderValuesArray,
@@ -297,7 +274,8 @@ export class ExchangeWrapper extends ContractWrapper {
            sArray,
            {
                from: takerAddress,
-                gas,
+                gas: orderTransactionOpts.gasLimit,
+                gasPrice: orderTransactionOpts.gasPrice,
            },
        );
        return txHash;
@@ -321,11 +299,11 @@ export class ExchangeWrapper extends ContractWrapper {
     * @param   orderTransactionOpts                            Optional arguments this method accepts.
     * @return  Transaction hash.
     */
-    @decorators.contractCallErrorHandler
+    @decorators.asyncZeroExErrorHandler
    public async batchFillOrdersAsync(orderFillRequests: OrderFillRequest[],
                                      shouldThrowOnInsufficientBalanceOrAllowance: boolean,
                                      takerAddress: string,
-                                      orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+                                      orderTransactionOpts: OrderTransactionOpts = {}): Promise<string> {
        assert.doesConformToSchema('orderFillRequests', orderFillRequests, schemas.orderFillRequestsSchema);
        const exchangeContractAddresses = _.map(
            orderFillRequests,
@@ -335,12 +313,12 @@ export class ExchangeWrapper extends ContractWrapper {
                                       ExchangeContractErrs.BatchOrdersMustHaveSameExchangeAddress);
        assert.isBoolean('shouldThrowOnInsufficientBalanceOrAllowance', shouldThrowOnInsufficientBalanceOrAllowance);
        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
-            SHOULD_VALIDATE_BY_DEFAULT :
-            orderTransactionOpts.shouldValidate;
+        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate) ?
+                               SHOULD_VALIDATE_BY_DEFAULT :
+                               orderTransactionOpts.shouldValidate;
        if (shouldValidate) {
-            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            const zrxTokenAddress = this.getZRXTokenAddress();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
            for (const orderFillRequest of orderFillRequests) {
                await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
                    exchangeTradeEmulator, orderFillRequest.signedOrder, orderFillRequest.takerTokenFillAmount,
@@ -367,18 +345,6 @@ export class ExchangeWrapper extends ContractWrapper {
        );

        const exchangeInstance = await this._getExchangeContractAsync();
-        const gas = await exchangeInstance.batchFillOrders.estimateGasAsync(
-            orderAddressesArray,
-            orderValuesArray,
-            fillTakerTokenAmounts,
-            shouldThrowOnInsufficientBalanceOrAllowance,
-            vArray,
-            rArray,
-            sArray,
-            {
-                from: takerAddress,
-            },
-        );
        const txHash = await exchangeInstance.batchFillOrders.sendTransactionAsync(
            orderAddressesArray,
            orderValuesArray,
@@ -389,7 +355,8 @@ export class ExchangeWrapper extends ContractWrapper {
            sArray,
            {
                from: takerAddress,
-                gas,
+                gas: orderTransactionOpts.gasLimit,
+                gasPrice: orderTransactionOpts.gasPrice,
            },
        );
        return txHash;
@@ -405,39 +372,27 @@ export class ExchangeWrapper extends ContractWrapper {
     * @param   orderTransactionOpts    Optional arguments this method accepts.
     * @return  Transaction hash.
     */
-    @decorators.contractCallErrorHandler
+    @decorators.asyncZeroExErrorHandler
    public async fillOrKillOrderAsync(signedOrder: SignedOrder, fillTakerTokenAmount: BigNumber,
                                      takerAddress: string,
-                                      orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+                                      orderTransactionOpts: OrderTransactionOpts = {}): Promise<string> {
        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);

        const exchangeInstance = await this._getExchangeContractAsync();

-        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
-            SHOULD_VALIDATE_BY_DEFAULT :
-            orderTransactionOpts.shouldValidate;
+        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate) ?
+                               SHOULD_VALIDATE_BY_DEFAULT :
+                               orderTransactionOpts.shouldValidate;
        if (shouldValidate) {
-            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            const zrxTokenAddress = this.getZRXTokenAddress();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
            await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
                exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
        }

        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(signedOrder);
-
-        const gas = await exchangeInstance.fillOrKillOrder.estimateGasAsync(
-            orderAddresses,
-            orderValues,
-            fillTakerTokenAmount,
-            signedOrder.ecSignature.v,
-            signedOrder.ecSignature.r,
-            signedOrder.ecSignature.s,
-            {
-                from: takerAddress,
-            },
-        );
        const txHash = await exchangeInstance.fillOrKillOrder.sendTransactionAsync(
            orderAddresses,
            orderValues,
@@ -447,7 +402,8 @@ export class ExchangeWrapper extends ContractWrapper {
            signedOrder.ecSignature.s,
            {
                from: takerAddress,
-                gas,
+                gas: orderTransactionOpts.gasLimit,
+                gasPrice: orderTransactionOpts.gasPrice,
            },
        );
        return txHash;
@@ -461,10 +417,10 @@ export class ExchangeWrapper extends ContractWrapper {
     * @param   orderTransactionOpts        Optional arguments this method accepts.
     * @return  Transaction hash.
     */
-    @decorators.contractCallErrorHandler
+    @decorators.asyncZeroExErrorHandler
    public async batchFillOrKillAsync(orderFillRequests: OrderFillRequest[],
                                      takerAddress: string,
-                                      orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+                                      orderTransactionOpts: OrderTransactionOpts = {}): Promise<string> {
        assert.doesConformToSchema('orderFillRequests', orderFillRequests,
                                   schemas.orderFillRequestsSchema);
        const exchangeContractAddresses = _.map(
@@ -479,12 +435,12 @@ export class ExchangeWrapper extends ContractWrapper {
        }
        const exchangeInstance = await this._getExchangeContractAsync();

-        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
-            SHOULD_VALIDATE_BY_DEFAULT :
-            orderTransactionOpts.shouldValidate;
+        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate) ?
+                               SHOULD_VALIDATE_BY_DEFAULT :
+                               orderTransactionOpts.shouldValidate;
        if (shouldValidate) {
-            const zrxTokenAddress = await this.getZRXTokenAddressAsync();
-            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+            const zrxTokenAddress = this.getZRXTokenAddress();
+            const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
            for (const orderFillRequest of orderFillRequests) {
                await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
                    exchangeTradeEmulator, orderFillRequest.signedOrder, orderFillRequest.takerTokenFillAmount,
@@ -506,18 +462,6 @@ export class ExchangeWrapper extends ContractWrapper {
        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
        const [orderAddresses, orderValues, fillTakerTokenAmounts, vParams, rParams, sParams] =
              _.unzip<any>(orderAddressesValuesAndTakerTokenFillAmounts);
-
-        const gas = await exchangeInstance.batchFillOrKillOrders.estimateGasAsync(
-            orderAddresses,
-            orderValues,
-            fillTakerTokenAmounts,
-            vParams,
-            rParams,
-            sParams,
-            {
-                from: takerAddress,
-            },
-        );
        const txHash = await exchangeInstance.batchFillOrKillOrders.sendTransactionAsync(
            orderAddresses,
            orderValues,
@@ -527,7 +471,8 @@ export class ExchangeWrapper extends ContractWrapper {
            sParams,
            {
                from: takerAddress,
-                gas,
+                gas: orderTransactionOpts.gasLimit,
+                gasPrice: orderTransactionOpts.gasPrice,
            },
        );
        return txHash;
@@ -540,42 +485,35 @@ export class ExchangeWrapper extends ContractWrapper {
     * @param   transactionOpts         Optional arguments this method accepts.
     * @return  Transaction hash.
     */
-    @decorators.contractCallErrorHandler
+    @decorators.asyncZeroExErrorHandler
    public async cancelOrderAsync(order: Order|SignedOrder,
                                  cancelTakerTokenAmount: BigNumber,
-                                  orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+                                  orderTransactionOpts: OrderTransactionOpts = {}): Promise<string> {
        assert.doesConformToSchema('order', order, schemas.orderSchema);
        assert.isValidBaseUnitAmount('takerTokenCancelAmount', cancelTakerTokenAmount);
        await assert.isSenderAddressAsync('order.maker', order.maker, this._web3Wrapper);

        const exchangeInstance = await this._getExchangeContractAsync();

-        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
-            SHOULD_VALIDATE_BY_DEFAULT :
-            orderTransactionOpts.shouldValidate;
+        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate) ?
+                               SHOULD_VALIDATE_BY_DEFAULT :
+                               orderTransactionOpts.shouldValidate;
        if (shouldValidate) {
            const orderHash = utils.getOrderHashHex(order);
            const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
-            await this._orderValidationUtils.validateCancelOrderThrowIfInvalidAsync(
+            OrderValidationUtils.validateCancelOrderThrowIfInvalid(
                order, cancelTakerTokenAmount, unavailableTakerTokenAmount);
        }

        const [orderAddresses, orderValues] = ExchangeWrapper._getOrderAddressesAndValues(order);
-        const gas = await exchangeInstance.cancelOrder.estimateGasAsync(
-            orderAddresses,
-            orderValues,
-            cancelTakerTokenAmount,
-            {
-                from: order.maker,
-            },
-        );
        const txHash = await exchangeInstance.cancelOrder.sendTransactionAsync(
            orderAddresses,
            orderValues,
            cancelTakerTokenAmount,
            {
                from: order.maker,
-                gas,
+                gas: orderTransactionOpts.gasLimit,
+                gasPrice: orderTransactionOpts.gasPrice,
            },
        );
        return txHash;
@@ -588,9 +526,9 @@ export class ExchangeWrapper extends ContractWrapper {
     * @param   transactionOpts             Optional arguments this method accepts.
     * @return  Transaction hash.
     */
-    @decorators.contractCallErrorHandler
+    @decorators.asyncZeroExErrorHandler
    public async batchCancelOrdersAsync(orderCancellationRequests: OrderCancellationRequest[],
-                                        orderTransactionOpts?: OrderTransactionOpts): Promise<string> {
+                                        orderTransactionOpts: OrderTransactionOpts = {}): Promise<string> {
        assert.doesConformToSchema('orderCancellationRequests', orderCancellationRequests,
                                   schemas.orderCancellationRequestsSchema);
        const exchangeContractAddresses = _.map(
@@ -603,14 +541,14 @@ export class ExchangeWrapper extends ContractWrapper {
        assert.hasAtMostOneUniqueValue(makers, ExchangeContractErrs.MultipleMakersInSingleCancelBatchDisallowed);
        const maker = makers[0];
        await assert.isSenderAddressAsync('maker', maker, this._web3Wrapper);
-        const shouldValidate = _.isUndefined(orderTransactionOpts) ?
-            SHOULD_VALIDATE_BY_DEFAULT :
-            orderTransactionOpts.shouldValidate;
+        const shouldValidate = _.isUndefined(orderTransactionOpts.shouldValidate) ?
+                               SHOULD_VALIDATE_BY_DEFAULT :
+                               orderTransactionOpts.shouldValidate;
        if (shouldValidate) {
            for (const orderCancellationRequest of orderCancellationRequests) {
                const orderHash = utils.getOrderHashHex(orderCancellationRequest.order);
                const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
-                await this._orderValidationUtils.validateCancelOrderThrowIfInvalidAsync(
+                OrderValidationUtils.validateCancelOrderThrowIfInvalid(
                    orderCancellationRequest.order, orderCancellationRequest.takerTokenCancelAmount,
                    unavailableTakerTokenAmount,
                );
@@ -630,21 +568,14 @@ export class ExchangeWrapper extends ContractWrapper {
        // We use _.unzip<any> because _.unzip doesn't type check if values have different types :'(
        const [orderAddresses, orderValues, cancelTakerTokenAmounts] =
            _.unzip<any>(orderAddressesValuesAndTakerTokenCancelAmounts);
-        const gas = await exchangeInstance.batchCancelOrders.estimateGasAsync(
-            orderAddresses,
-            orderValues,
-            cancelTakerTokenAmounts,
-            {
-                from: maker,
-            },
-        );
        const txHash = await exchangeInstance.batchCancelOrders.sendTransactionAsync(
            orderAddresses,
            orderValues,
            cancelTakerTokenAmounts,
            {
                from: maker,
-                gas,
+                gas: orderTransactionOpts.gasLimit,
+                gasPrice: orderTransactionOpts.gasPrice,
            },
        );
        return txHash;
@@ -657,13 +588,13 @@ export class ExchangeWrapper extends ContractWrapper {
     * @param   callback            Callback that gets called when a log is added/removed
     * @return Subscription token used later to unsubscribe
     */
-    public async subscribeAsync<ArgsType extends ExchangeContractEventArgs>(
+    public subscribe<ArgsType extends ExchangeContractEventArgs>(
        eventName: ExchangeEvents, indexFilterValues: IndexedFilterValues,
-        callback: EventCallback<ArgsType>): Promise<string> {
+        callback: EventCallback<ArgsType>): string {
        assert.doesBelongToStringEnum('eventName', eventName, ExchangeEvents);
        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
        assert.isFunction('callback', callback);
-        const exchangeContractAddress = await this.getContractAddressAsync();
+        const exchangeContractAddress = this.getContractAddress();
        const subscriptionToken = this._subscribe<ArgsType>(
            exchangeContractAddress, eventName, indexFilterValues, artifacts.ExchangeArtifact.abi, callback,
        );
@@ -676,23 +607,29 @@ export class ExchangeWrapper extends ContractWrapper {
    public unsubscribe(subscriptionToken: string): void {
        this._unsubscribe(subscriptionToken);
    }
+    /**
+     * Cancels all existing subscriptions
+     */
+    public unsubscribeAll(): void {
+        super.unsubscribeAll();
+    }
    /**
     * Gets historical logs without creating a subscription
     * @param   eventName           The exchange contract event you would like to subscribe to.
-     * @param   subscriptionOpts    Subscriptions options that let you configure the subscription.
+     * @param   blockRange          Block range to get logs from.
     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
     *                              the value is the value you are interested in. E.g `{_from: aUserAddressHex}`
     * @return  Array of logs that match the parameters
     */
    public async getLogsAsync<ArgsType extends ExchangeContractEventArgs>(
-        eventName: ExchangeEvents, subscriptionOpts: SubscriptionOpts, indexFilterValues: IndexedFilterValues,
+        eventName: ExchangeEvents, blockRange: BlockRange, indexFilterValues: IndexedFilterValues,
    ): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
        assert.doesBelongToStringEnum('eventName', eventName, ExchangeEvents);
-        assert.doesConformToSchema('subscriptionOpts', subscriptionOpts, schemas.subscriptionOptsSchema);
+        assert.doesConformToSchema('blockRange', blockRange, schemas.blockRangeSchema);
        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
-        const exchangeContractAddress = await this.getContractAddressAsync();
+        const exchangeContractAddress = this.getContractAddress();
        const logs = await this._getLogsAsync<ArgsType>(
-            exchangeContractAddress, eventName, subscriptionOpts, indexFilterValues, artifacts.ExchangeArtifact.abi,
+            exchangeContractAddress, eventName, blockRange, indexFilterValues, artifacts.ExchangeArtifact.abi,
        );
        return logs;
    }
@@ -701,10 +638,9 @@ export class ExchangeWrapper extends ContractWrapper {
     * that the user-passed web3 provider is connected to.
     * @returns The Ethereum address of the Exchange contract being used.
     */
-    public async getContractAddressAsync(): Promise<string> {
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const exchangeAddress = exchangeInstance.address;
-        return exchangeAddress;
+    public getContractAddress(): string {
+        const contractAddress = this._getContractAddress(artifacts.ExchangeArtifact, this._contractAddressIfExists);
+        return contractAddress;
    }
    /**
     * Checks if order is still fillable and throws an error otherwise. Useful for orderbook
@@ -719,9 +655,9 @@ export class ExchangeWrapper extends ContractWrapper {
        signedOrder: SignedOrder, opts?: ValidateOrderFillableOpts,
    ): Promise<void> {
        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
-        const zrxTokenAddress = await this.getZRXTokenAddressAsync();
+        const zrxTokenAddress = this.getZRXTokenAddress();
        const expectedFillTakerTokenAmount = !_.isUndefined(opts) ? opts.expectedFillTakerTokenAmount : undefined;
-        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
        await this._orderValidationUtils.validateOrderFillableOrThrowAsync(
            exchangeTradeEmulator, signedOrder, zrxTokenAddress, expectedFillTakerTokenAmount,
        );
@@ -740,8 +676,8 @@ export class ExchangeWrapper extends ContractWrapper {
        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const zrxTokenAddress = await this.getZRXTokenAddressAsync();
-        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+        const zrxTokenAddress = this.getZRXTokenAddress();
+        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
        await this._orderValidationUtils.validateFillOrderThrowIfInvalidAsync(
            exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
    }
@@ -757,7 +693,7 @@ export class ExchangeWrapper extends ContractWrapper {
        assert.isValidBaseUnitAmount('cancelTakerTokenAmount', cancelTakerTokenAmount);
        const orderHash = utils.getOrderHashHex(order);
        const unavailableTakerTokenAmount = await this.getUnavailableTakerAmountAsync(orderHash);
-        await this._orderValidationUtils.validateCancelOrderThrowIfInvalidAsync(
+        OrderValidationUtils.validateCancelOrderThrowIfInvalid(
            order, cancelTakerTokenAmount, unavailableTakerTokenAmount);
    }
    /**
@@ -774,8 +710,8 @@ export class ExchangeWrapper extends ContractWrapper {
        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
        assert.isValidBaseUnitAmount('fillTakerTokenAmount', fillTakerTokenAmount);
        await assert.isSenderAddressAsync('takerAddress', takerAddress, this._web3Wrapper);
-        const zrxTokenAddress = await this.getZRXTokenAddressAsync();
-        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper);
+        const zrxTokenAddress = this.getZRXTokenAddress();
+        const exchangeTradeEmulator = new ExchangeTransferSimulator(this._tokenWrapper, BlockParamLiteral.Latest);
        await this._orderValidationUtils.validateFillOrKillOrderThrowIfInvalidAsync(
            exchangeTradeEmulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress);
    }
@@ -819,12 +755,13 @@ export class ExchangeWrapper extends ContractWrapper {
     * Returns the ZRX token address used by the exchange contract.
     * @return Address of ZRX token
     */
-    public async getZRXTokenAddressAsync(): Promise<string> {
-        const exchangeInstance = await this._getExchangeContractAsync();
-        const ZRXtokenAddress = await exchangeInstance.ZRX_TOKEN_CONTRACT.callAsync();
-        return ZRXtokenAddress;
+    public getZRXTokenAddress(): string {
+        const contractAddress = this._getContractAddress(
+            artifacts.ZRXArtifact, this._zrxContractAddressIfExists,
+        );
+        return contractAddress;
    }
-    private async _invalidateContractInstancesAsync(): Promise<void> {
+    private _invalidateContractInstances(): void {
        this.unsubscribeAll();
        delete this._exchangeContractIfExists;
    }
@@ -855,10 +792,11 @@ export class ExchangeWrapper extends ContractWrapper {
        if (!_.isUndefined(this._exchangeContractIfExists)) {
            return this._exchangeContractIfExists;
        }
-        const contractInstance = await this._instantiateContractIfExistsAsync<ExchangeContract>(
+        const web3ContractInstance = await this._instantiateContractIfExistsAsync(
            artifacts.ExchangeArtifact, this._contractAddressIfExists,
        );
-        this._exchangeContractIfExists = contractInstance as ExchangeContract;
+        const contractInstance = new ExchangeContract(web3ContractInstance, this._web3Wrapper.getContractDefaults());
+        this._exchangeContractIfExists = contractInstance;
        return this._exchangeContractIfExists;
    }
    private async _getTokenTransferProxyAddressAsync(): Promise<string> {
@@ -867,4 +805,4 @@ export class ExchangeWrapper extends ContractWrapper {
        const tokenTransferProxyAddressLowerCase = tokenTransferProxyAddress.toLowerCase();
        return tokenTransferProxyAddressLowerCase;
    }
-}
+} // tslint:disable:max-file-line-count
--- a/packages/0x.js/src/contract_wrappers/generated/.gitignore
+++ b/packages/0x.js/src/contract_wrappers/generated/.gitignore
@@ -0,0 +1,6 @@
+dummy_token.ts
+ether_token.ts
+exchange.ts
+token_registry.ts
+token_transfer_proxy.ts
+token.ts
--- a/packages/0x.js/src/contract_wrappers/generated/base_contract.ts
+++ b/packages/0x.js/src/contract_wrappers/generated/base_contract.ts
@@ -0,0 +1,33 @@
+import {TxData, TxDataPayable} from '@0xproject/types';
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
+
+export class BaseContract {
+    protected web3ContractInstance: Web3.ContractInstance;
+    protected defaults: Partial<TxData>;
+    protected async applyDefaultsToTxDataAsync<T extends TxData|TxDataPayable>(
+        txData: T,
+        estimateGasAsync?: (txData: T) => Promise<number>,
+    ): Promise<TxData> {
+        // Gas amount sourced with the following priorities:
+        // 1. Optional param passed in to public method call
+        // 2. Global config passed in at library instantiation
+        // 3. Gas estimate calculation + safety margin
+        const removeUndefinedProperties = _.pickBy;
+        const txDataWithDefaults = {
+            ...removeUndefinedProperties(this.defaults),
+            ...removeUndefinedProperties(txData as any),
+            // HACK: TS can't prove that T is spreadable.
+            // Awaiting https://github.com/Microsoft/TypeScript/pull/13288 to be merged
+        };
+        if (_.isUndefined(txDataWithDefaults.gas) && !_.isUndefined(estimateGasAsync)) {
+            const estimatedGas = await estimateGasAsync(txData);
+            txDataWithDefaults.gas = estimatedGas;
+        }
+        return txDataWithDefaults;
+    }
+    constructor(web3ContractInstance: Web3.ContractInstance, defaults: Partial<TxData>) {
+        this.web3ContractInstance = web3ContractInstance;
+        this.defaults = defaults;
+    }
+}
--- a/packages/0x.js/src/contract_wrappers/token_registry_wrapper.ts
+++ b/packages/0x.js/src/contract_wrappers/token_registry_wrapper.ts
@@ -1,10 +1,13 @@
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
 import * as _ from 'lodash';
-import {Web3Wrapper} from '../web3_wrapper';
-import {assert} from '../utils/assert';
-import {Token, TokenRegistryContract, TokenMetadata} from '../types';
-import {constants} from '../utils/constants';
-import {ContractWrapper} from './contract_wrapper';
+
 import {artifacts} from '../artifacts';
+import {Token, TokenMetadata} from '../types';
+import {assert} from '../utils/assert';
+import {constants} from '../utils/constants';
+
+import {ContractWrapper} from './contract_wrapper';
+import {TokenRegistryContract} from './generated/token_registry';

 /**
 * This class includes all the functionality related to interacting with the 0x Token Registry smart contract.
@@ -12,8 +15,20 @@ import {artifacts} from '../artifacts';
 export class TokenRegistryWrapper extends ContractWrapper {
    private _tokenRegistryContractIfExists?: TokenRegistryContract;
    private _contractAddressIfExists?: string;
-    constructor(web3Wrapper: Web3Wrapper, contractAddressIfExists?: string) {
-        super(web3Wrapper);
+    private static _createTokenFromMetadata(metadata: TokenMetadata): Token|undefined {
+        if (metadata[0] === constants.NULL_ADDRESS) {
+            return undefined;
+        }
+        const token = {
+            address: metadata[0],
+            name: metadata[1],
+            symbol: metadata[2],
+            decimals: metadata[3].toNumber(),
+        };
+        return token;
+    }
+    constructor(web3Wrapper: Web3Wrapper, networkId: number, contractAddressIfExists?: string) {
+        super(web3Wrapper, networkId);
        this._contractAddressIfExists = contractAddressIfExists;
    }
    /**
@@ -21,12 +36,10 @@ export class TokenRegistryWrapper extends ContractWrapper {
     * @return  An array of objects that conform to the Token interface.
     */
    public async getTokensAsync(): Promise<Token[]> {
-        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
-
        const addresses = await this.getTokenAddressesAsync();
        const tokenPromises: Array<Promise<Token|undefined>> = _.map(
            addresses,
-            (address: string) => (this.getTokenIfExistsAsync(address)),
+            async (address: string) => this.getTokenIfExistsAsync(address),
        );
        const tokens = await Promise.all(tokenPromises);
        return tokens as Token[];
@@ -49,7 +62,7 @@ export class TokenRegistryWrapper extends ContractWrapper {

        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
        const metadata = await tokenRegistryContract.getTokenMetaData.callAsync(address);
-        const token = this._createTokenFromMetadata(metadata);
+        const token = TokenRegistryWrapper._createTokenFromMetadata(metadata);
        return token;
    }
    public async getTokenAddressBySymbolIfExistsAsync(symbol: string): Promise<string|undefined> {
@@ -74,14 +87,14 @@ export class TokenRegistryWrapper extends ContractWrapper {
        assert.isString('symbol', symbol);
        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
        const metadata = await tokenRegistryContract.getTokenBySymbol.callAsync(symbol);
-        const token = this._createTokenFromMetadata(metadata);
+        const token = TokenRegistryWrapper._createTokenFromMetadata(metadata);
        return token;
    }
    public async getTokenByNameIfExistsAsync(name: string): Promise<Token|undefined> {
        assert.isString('name', name);
        const tokenRegistryContract = await this._getTokenRegistryContractAsync();
        const metadata = await tokenRegistryContract.getTokenByName.callAsync(name);
-        const token = this._createTokenFromMetadata(metadata);
+        const token = TokenRegistryWrapper._createTokenFromMetadata(metadata);
        return token;
    }
    /**
@@ -89,22 +102,11 @@ export class TokenRegistryWrapper extends ContractWrapper {
     * that the user-passed web3 provider is connected to.
     * @returns The Ethereum address of the TokenRegistry contract being used.
     */
-    public async getContractAddressAsync(): Promise<string> {
-        const tokenRegistryInstance = await this._getTokenRegistryContractAsync();
-        const tokenRegistryAddress = tokenRegistryInstance.address;
-        return tokenRegistryAddress;
-    }
-    private _createTokenFromMetadata(metadata: TokenMetadata): Token|undefined {
-        if (metadata[0] === constants.NULL_ADDRESS) {
-            return undefined;
-        }
-        const token = {
-            address: metadata[0],
-            name: metadata[1],
-            symbol: metadata[2],
-            decimals: metadata[3].toNumber(),
-        };
-        return token;
+    public getContractAddress(): string {
+        const contractAddress = this._getContractAddress(
+            artifacts.TokenRegistryArtifact, this._contractAddressIfExists,
+        );
+        return contractAddress;
    }
    private _invalidateContractInstance(): void {
        delete this._tokenRegistryContractIfExists;
@@ -113,10 +115,13 @@ export class TokenRegistryWrapper extends ContractWrapper {
        if (!_.isUndefined(this._tokenRegistryContractIfExists)) {
            return this._tokenRegistryContractIfExists;
        }
-        const contractInstance = await this._instantiateContractIfExistsAsync<TokenRegistryContract>(
+        const web3ContractInstance = await this._instantiateContractIfExistsAsync(
            artifacts.TokenRegistryArtifact, this._contractAddressIfExists,
        );
-        this._tokenRegistryContractIfExists = contractInstance as TokenRegistryContract;
+        const contractInstance = new TokenRegistryContract(
+            web3ContractInstance, this._web3Wrapper.getContractDefaults(),
+        );
+        this._tokenRegistryContractIfExists = contractInstance;
        return this._tokenRegistryContractIfExists;
    }
 }
--- a/packages/0x.js/src/contract_wrappers/token_transfer_proxy_wrapper.ts
+++ b/packages/0x.js/src/contract_wrappers/token_transfer_proxy_wrapper.ts
@@ -1,18 +1,20 @@
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
 import * as _ from 'lodash';
-import {Web3Wrapper} from '../web3_wrapper';
-import {ContractWrapper} from './contract_wrapper';
+
 import {artifacts} from '../artifacts';
-import {TokenTransferProxyContract} from '../types';
+
+import {ContractWrapper} from './contract_wrapper';
+import {TokenTransferProxyContract} from './generated/token_transfer_proxy';

 /**
 * This class includes the functionality related to interacting with the TokenTransferProxy contract.
 */
 export class TokenTransferProxyWrapper extends ContractWrapper {
    private _tokenTransferProxyContractIfExists?: TokenTransferProxyContract;
-    private _tokenTransferProxyContractAddressFetcher: () => Promise<string>;
-    constructor(web3Wrapper: Web3Wrapper, tokenTransferProxyContractAddressFetcher: () => Promise<string>) {
-        super(web3Wrapper);
-        this._tokenTransferProxyContractAddressFetcher = tokenTransferProxyContractAddressFetcher;
+    private _contractAddressIfExists?: string;
+    constructor(web3Wrapper: Web3Wrapper, networkId: number, contractAddressIfExists?: string) {
+        super(web3Wrapper, networkId);
+        this._contractAddressIfExists = contractAddressIfExists;
    }
    /**
     * Check if the Exchange contract address is authorized by the TokenTransferProxy contract.
@@ -38,10 +40,11 @@ export class TokenTransferProxyWrapper extends ContractWrapper {
     * that the user-passed web3 provider is connected to.
     * @returns The Ethereum address of the TokenTransferProxy contract being used.
     */
-    public async getContractAddressAsync(): Promise<string> {
-        const proxyInstance = await this._getTokenTransferProxyContractAsync();
-        const proxyAddress = proxyInstance.address;
-        return proxyAddress;
+    public getContractAddress(): string {
+        const contractAddress = this._getContractAddress(
+            artifacts.TokenTransferProxyArtifact, this._contractAddressIfExists,
+        );
+        return contractAddress;
    }
    private _invalidateContractInstance(): void {
        delete this._tokenTransferProxyContractIfExists;
@@ -50,11 +53,13 @@ export class TokenTransferProxyWrapper extends ContractWrapper {
        if (!_.isUndefined(this._tokenTransferProxyContractIfExists)) {
            return this._tokenTransferProxyContractIfExists;
        }
-        const contractAddress = await this._tokenTransferProxyContractAddressFetcher();
-        const contractInstance = await this._instantiateContractIfExistsAsync<TokenTransferProxyContract>(
-            artifacts.TokenTransferProxyArtifact, contractAddress,
+        const web3ContractInstance = await this._instantiateContractIfExistsAsync(
+            artifacts.TokenTransferProxyArtifact, this._contractAddressIfExists,
        );
-        this._tokenTransferProxyContractIfExists = contractInstance as TokenTransferProxyContract;
+        const contractInstance = new TokenTransferProxyContract(
+            web3ContractInstance, this._web3Wrapper.getContractDefaults(),
+        );
+        this._tokenTransferProxyContractIfExists = contractInstance;
        return this._tokenTransferProxyContractIfExists;
    }
 }
--- a/packages/0x.js/src/contract_wrappers/token_wrapper.ts
+++ b/packages/0x.js/src/contract_wrappers/token_wrapper.ts
@@ -1,25 +1,27 @@
-import * as _ from 'lodash';
-import BigNumber from 'bignumber.js';
 import {schemas} from '@0xproject/json-schemas';
-import {Web3Wrapper} from '../web3_wrapper';
-import {assert} from '../utils/assert';
-import {constants} from '../utils/constants';
-import {ContractWrapper} from './contract_wrapper';
-import {AbiDecoder} from '../utils/abi_decoder';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
+import BigNumber from 'bignumber.js';
+import * as _ from 'lodash';
+
 import {artifacts} from '../artifacts';
 import {
-    TokenContract,
-    ZeroExError,
-    TokenEvents,
-    IndexedFilterValues,
-    SubscriptionOpts,
-    MethodOpts,
-    LogWithDecodedArgs,
+    BlockRange,
    EventCallback,
+    IndexedFilterValues,
+    LogWithDecodedArgs,
+    MethodOpts,
    TokenContractEventArgs,
+    TokenEvents,
+    TransactionOpts,
+    ZeroExError,
 } from '../types';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {assert} from '../utils/assert';
+import {constants} from '../utils/constants';

-const ALLOWANCE_TO_ZERO_GAS_AMOUNT = 47275;
+import {ContractWrapper} from './contract_wrapper';
+import {TokenContract} from './generated/token';
+import {TokenTransferProxyWrapper} from './token_transfer_proxy_wrapper';

 /**
 * This class includes all the functionality related to interacting with ERC20 token contracts.
@@ -29,12 +31,12 @@ const ALLOWANCE_TO_ZERO_GAS_AMOUNT = 47275;
 export class TokenWrapper extends ContractWrapper {
    public UNLIMITED_ALLOWANCE_IN_BASE_UNITS = constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
    private _tokenContractsByAddress: {[address: string]: TokenContract};
-    private _tokenTransferProxyContractAddressFetcher: () => Promise<string>;
-    constructor(web3Wrapper: Web3Wrapper, abiDecoder: AbiDecoder,
-                tokenTransferProxyContractAddressFetcher: () => Promise<string>) {
-        super(web3Wrapper, abiDecoder);
+    private _tokenTransferProxyWrapper: TokenTransferProxyWrapper;
+    constructor(web3Wrapper: Web3Wrapper, networkId: number, abiDecoder: AbiDecoder,
+                tokenTransferProxyWrapper: TokenTransferProxyWrapper) {
+        super(web3Wrapper, networkId, abiDecoder);
        this._tokenContractsByAddress = {};
-        this._tokenTransferProxyContractAddressFetcher = tokenTransferProxyContractAddressFetcher;
+        this._tokenTransferProxyWrapper = tokenTransferProxyWrapper;
    }
    /**
     * Retrieves an owner's ERC20 token balance.
@@ -63,24 +65,21 @@ export class TokenWrapper extends ContractWrapper {
     *                              for spenderAddress.
     * @param   spenderAddress      The hex encoded user Ethereum address who will be able to spend the set allowance.
     * @param   amountInBaseUnits   The allowance amount you would like to set.
+     * @param   txOpts              Transaction parameters.
     * @return Transaction hash.
     */
    public async setAllowanceAsync(tokenAddress: string, ownerAddress: string, spenderAddress: string,
-                                   amountInBaseUnits: BigNumber): Promise<string> {
+                                   amountInBaseUnits: BigNumber, txOpts: TransactionOpts = {}): Promise<string> {
        await assert.isSenderAddressAsync('ownerAddress', ownerAddress, this._web3Wrapper);
        assert.isETHAddressHex('spenderAddress', spenderAddress);
        assert.isETHAddressHex('tokenAddress', tokenAddress);
        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);

        const tokenContract = await this._getTokenContractAsync(tokenAddress);
-        // Hack: for some reason default estimated gas amount causes `base fee exceeds gas limit` exception
-        // on testrpc. Probably related to https://github.com/ethereumjs/testrpc/issues/294
-        // TODO: Debug issue in testrpc and submit a PR, then remove this hack
-        const networkIdIfExists = await this._web3Wrapper.getNetworkIdIfExistsAsync();
-        const gas = networkIdIfExists === constants.TESTRPC_NETWORK_ID ? ALLOWANCE_TO_ZERO_GAS_AMOUNT : undefined;
        const txHash = await tokenContract.approve.sendTransactionAsync(spenderAddress, amountInBaseUnits, {
            from: ownerAddress,
-            gas,
+            gas: txOpts.gasLimit,
+            gasPrice: txOpts.gasPrice,
        });
        return txHash;
    }
@@ -93,12 +92,13 @@ export class TokenWrapper extends ContractWrapper {
     * @param   ownerAddress        The hex encoded user Ethereum address who would like to set an allowance
     *                              for spenderAddress.
     * @param   spenderAddress      The hex encoded user Ethereum address who will be able to spend the set allowance.
+     * @param   txOpts              Transaction parameters.
     * @return Transaction hash.
     */
    public async setUnlimitedAllowanceAsync(tokenAddress: string, ownerAddress: string,
-                                            spenderAddress: string): Promise<string> {
+                                            spenderAddress: string, txOpts: TransactionOpts = {}): Promise<string> {
        const txHash = await this.setAllowanceAsync(
-            tokenAddress, ownerAddress, spenderAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+            tokenAddress, ownerAddress, spenderAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS, txOpts,
        );
        return txHash;
    }
@@ -133,7 +133,7 @@ export class TokenWrapper extends ContractWrapper {
        assert.isETHAddressHex('ownerAddress', ownerAddress);
        assert.isETHAddressHex('tokenAddress', tokenAddress);

-        const proxyAddress = await this._getTokenTransferProxyAddressAsync();
+        const proxyAddress = this._tokenTransferProxyWrapper.getContractAddress();
        const allowanceInBaseUnits = await this.getAllowanceAsync(tokenAddress, ownerAddress, proxyAddress, methodOpts);
        return allowanceInBaseUnits;
    }
@@ -144,16 +144,19 @@ export class TokenWrapper extends ContractWrapper {
     * @param   ownerAddress        The hex encoded user Ethereum address who is setting an allowance
     *                              for the Proxy contract.
     * @param   amountInBaseUnits   The allowance amount specified in baseUnits.
+     * @param   txOpts              Transaction parameters.
     * @return Transaction hash.
     */
    public async setProxyAllowanceAsync(tokenAddress: string, ownerAddress: string,
-                                        amountInBaseUnits: BigNumber): Promise<string> {
+                                        amountInBaseUnits: BigNumber, txOpts: TransactionOpts = {}): Promise<string> {
        assert.isETHAddressHex('ownerAddress', ownerAddress);
        assert.isETHAddressHex('tokenAddress', tokenAddress);
        assert.isValidBaseUnitAmount('amountInBaseUnits', amountInBaseUnits);

-        const proxyAddress = await this._getTokenTransferProxyAddressAsync();
-        const txHash = await this.setAllowanceAsync(tokenAddress, ownerAddress, proxyAddress, amountInBaseUnits);
+        const proxyAddress = this._tokenTransferProxyWrapper.getContractAddress();
+        const txHash = await this.setAllowanceAsync(
+            tokenAddress, ownerAddress, proxyAddress, amountInBaseUnits, txOpts,
+        );
        return txHash;
    }
    /**
@@ -164,11 +167,14 @@ export class TokenWrapper extends ContractWrapper {
     * @param   tokenAddress        The hex encoded contract Ethereum address where the ERC20 token is deployed.
     * @param   ownerAddress        The hex encoded user Ethereum address who is setting an allowance
     *                              for the Proxy contract.
+     * @param   txOpts              Transaction parameters.
     * @return Transaction hash.
     */
-    public async setUnlimitedProxyAllowanceAsync(tokenAddress: string, ownerAddress: string): Promise<string> {
+    public async setUnlimitedProxyAllowanceAsync(
+        tokenAddress: string, ownerAddress: string, txOpts: TransactionOpts = {},
+    ): Promise<string> {
        const txHash = await this.setProxyAllowanceAsync(
-            tokenAddress, ownerAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS,
+            tokenAddress, ownerAddress, this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS, txOpts,
        );
        return txHash;
    }
@@ -178,10 +184,11 @@ export class TokenWrapper extends ContractWrapper {
     * @param   fromAddress         The hex encoded user Ethereum address that will send the funds.
     * @param   toAddress           The hex encoded user Ethereum address that will receive the funds.
     * @param   amountInBaseUnits   The amount (specified in baseUnits) of the token to transfer.
+     * @param   txOpts              Transaction parameters.
     * @return Transaction hash.
     */
    public async transferAsync(tokenAddress: string, fromAddress: string, toAddress: string,
-                               amountInBaseUnits: BigNumber): Promise<string> {
+                               amountInBaseUnits: BigNumber, txOpts: TransactionOpts = {}): Promise<string> {
        assert.isETHAddressHex('tokenAddress', tokenAddress);
        await assert.isSenderAddressAsync('fromAddress', fromAddress, this._web3Wrapper);
        assert.isETHAddressHex('toAddress', toAddress);
@@ -196,6 +203,8 @@ export class TokenWrapper extends ContractWrapper {

        const txHash = await tokenContract.transfer.sendTransactionAsync(toAddress, amountInBaseUnits, {
            from: fromAddress,
+            gas: txOpts.gasLimit,
+            gasPrice: txOpts.gasPrice,
        });
        return txHash;
    }
@@ -210,10 +219,11 @@ export class TokenWrapper extends ContractWrapper {
     *                              `fromAddress` must have set an allowance to the `senderAddress`
     *                              before this call.
     * @param   amountInBaseUnits   The amount (specified in baseUnits) of the token to transfer.
+     * @param   txOpts              Transaction parameters.
     * @return Transaction hash.
     */
    public async transferFromAsync(tokenAddress: string, fromAddress: string, toAddress: string,
-                                   senderAddress: string, amountInBaseUnits: BigNumber):
+                                   senderAddress: string, amountInBaseUnits: BigNumber, txOpts: TransactionOpts = {}):
                                   Promise<string> {
        assert.isETHAddressHex('tokenAddress', tokenAddress);
        assert.isETHAddressHex('fromAddress', fromAddress);
@@ -237,6 +247,8 @@ export class TokenWrapper extends ContractWrapper {
            fromAddress, toAddress, amountInBaseUnits,
            {
                from: senderAddress,
+                gas: txOpts.gasLimit,
+                gasPrice: txOpts.gasPrice,
            },
        );
        return txHash;
@@ -269,28 +281,34 @@ export class TokenWrapper extends ContractWrapper {
    public unsubscribe(subscriptionToken: string): void {
        this._unsubscribe(subscriptionToken);
    }
+    /**
+     * Cancels all existing subscriptions
+     */
+    public unsubscribeAll(): void {
+        super.unsubscribeAll();
+    }
    /**
     * Gets historical logs without creating a subscription
     * @param   tokenAddress        An address of the token that emmited the logs.
     * @param   eventName           The token contract event you would like to subscribe to.
-     * @param   subscriptionOpts    Subscriptions options that let you configure the subscription.
+     * @param   blockRange          Block range to get logs from.
     * @param   indexFilterValues   An object where the keys are indexed args returned by the event and
     *                              the value is the value you are interested in. E.g `{_from: aUserAddressHex}`
     * @return  Array of logs that match the parameters
     */
    public async getLogsAsync<ArgsType extends TokenContractEventArgs>(
-        tokenAddress: string, eventName: TokenEvents, subscriptionOpts: SubscriptionOpts,
+        tokenAddress: string, eventName: TokenEvents, blockRange: BlockRange,
        indexFilterValues: IndexedFilterValues): Promise<Array<LogWithDecodedArgs<ArgsType>>> {
        assert.isETHAddressHex('tokenAddress', tokenAddress);
        assert.doesBelongToStringEnum('eventName', eventName, TokenEvents);
-        assert.doesConformToSchema('subscriptionOpts', subscriptionOpts, schemas.subscriptionOptsSchema);
+        assert.doesConformToSchema('blockRange', blockRange, schemas.blockRangeSchema);
        assert.doesConformToSchema('indexFilterValues', indexFilterValues, schemas.indexFilterValuesSchema);
        const logs = await this._getLogsAsync<ArgsType>(
-            tokenAddress, eventName, subscriptionOpts, indexFilterValues, artifacts.TokenArtifact.abi,
+            tokenAddress, eventName, blockRange, indexFilterValues, artifacts.TokenArtifact.abi,
        );
        return logs;
    }
-    private _invalidateContractInstancesAsync(): void {
+    private _invalidateContractInstances(): void {
        this.unsubscribeAll();
        this._tokenContractsByAddress = {};
    }
@@ -299,15 +317,14 @@ export class TokenWrapper extends ContractWrapper {
        if (!_.isUndefined(tokenContract)) {
            return tokenContract;
        }
-        const contractInstance = await this._instantiateContractIfExistsAsync<TokenContract>(
+        const web3ContractInstance = await this._instantiateContractIfExistsAsync(
            artifacts.TokenArtifact, tokenAddress,
        );
-        tokenContract = contractInstance as TokenContract;
+        const contractInstance = new TokenContract(
+            web3ContractInstance, this._web3Wrapper.getContractDefaults(),
+        );
+        tokenContract = contractInstance;
        this._tokenContractsByAddress[tokenAddress] = tokenContract;
        return tokenContract;
    }
-    private async _getTokenTransferProxyAddressAsync(): Promise<string> {
-        const tokenTransferProxyContractAddress = await this._tokenTransferProxyContractAddressFetcher();
-        return tokenTransferProxyContractAddress;
-    }
 }
--- a/packages/0x.js/src/globals.d.ts
+++ b/packages/0x.js/src/globals.d.ts
@@ -39,12 +39,6 @@ declare module 'compare-versions' {
    export = compareVersions;
 }

-// es6-promisify declarations
-declare function promisify(original: any, settings?: any): ((...arg: any[]) => Promise<any>);
-declare module 'es6-promisify' {
-    export = promisify;
-}
-
 declare module 'ethereumjs-abi' {
    const soliditySHA3: (argTypes: string[], args: any[]) => Buffer;
 }
--- a/packages/0x.js/src/index.ts
+++ b/packages/0x.js/src/index.ts
@@ -2,6 +2,7 @@ export {ZeroEx} from './0x';

 export {
    Order,
+    BlockParamLiteral,
    SignedOrder,
    ECSignature,
    ZeroExError,
@@ -12,7 +13,7 @@ export {
    ExchangeEvents,
    TokenEvents,
    IndexedFilterValues,
-    SubscriptionOpts,
+    BlockRange,
    BlockParam,
    OrderCancellationRequest,
    OrderFillRequest,
@@ -23,15 +24,19 @@ export {
    TransferContractEventArgs,
    ApprovalContractEventArgs,
    TokenContractEventArgs,
+    EtherTokenContractEventArgs,
+    WithdrawalContractEventArgs,
+    DepositContractEventArgs,
    ContractEventArgs,
    ContractEventArg,
    Web3Provider,
    ZeroExConfig,
-    TransactionReceipt,
+    EtherTokenEvents,
    TransactionReceiptWithDecodedLogs,
    LogWithDecodedArgs,
    MethodOpts,
    OrderTransactionOpts,
+    TransactionOpts,
    FilterObject,
    LogEvent,
    DecodedLogEvent,
@@ -41,3 +46,7 @@ export {
    OrderStateInvalid,
    OrderState,
 } from './types';
+
+export {
+    TransactionReceipt,
+} from '@0xproject/types';
--- a/packages/0x.js/src/order_watcher/event_watcher.ts
+++ b/packages/0x.js/src/order_watcher/event_watcher.ts
@@ -1,16 +1,14 @@
-import * as Web3 from 'web3';
+import {intervalUtils} from '@0xproject/utils';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
 import * as _ from 'lodash';
-import {Web3Wrapper} from '../web3_wrapper';
+import * as Web3 from 'web3';
+
 import {
    BlockParamLiteral,
-    EventCallback,
    EventWatcherCallback,
    ZeroExError,
 } from '../types';
-import {AbiDecoder} from '../utils/abi_decoder';
-import {intervalUtils} from '../utils/interval_utils';
 import {assert} from '../utils/assert';
-import {utils} from '../utils/utils';

 const DEFAULT_EVENT_POLLING_INTERVAL_MS = 200;

--- a/packages/0x.js/src/order_watcher/expiration_watcher.ts
+++ b/packages/0x.js/src/order_watcher/expiration_watcher.ts
@@ -1,10 +1,10 @@
-import * as _ from 'lodash';
+import {intervalUtils} from '@0xproject/utils';
 import {BigNumber} from 'bignumber.js';
 import {RBTree} from 'bintrees';
+import * as _ from 'lodash';
+
+import {ZeroExError} from '../types';
 import {utils} from '../utils/utils';
-import {intervalUtils} from '../utils/interval_utils';
-import {SignedOrder, ZeroExError} from '../types';
-import {ZeroEx} from '../0x';

 const DEFAULT_EXPIRATION_MARGIN_MS = 0;
 const DEFAULT_ORDER_EXPIRATION_CHECKING_INTERVAL_MS = 50;
@@ -29,12 +29,12 @@ export class ExpirationWatcher {
        const comparator = (lhs: string, rhs: string) => scoreFunction(lhs) - scoreFunction(rhs);
        this.orderHashByExpirationRBTree = new RBTree(comparator);
    }
-    public subscribe(callbackAsync: (orderHash: string) => Promise<void>): void {
+    public subscribe(callback: (orderHash: string) => void): void {
        if (!_.isUndefined(this.orderExpirationCheckingIntervalIdIfExists)) {
            throw new Error(ZeroExError.SubscriptionAlreadyPresent);
        }
        this.orderExpirationCheckingIntervalIdIfExists = intervalUtils.setAsyncExcludingInterval(
-            this.pruneExpiredOrdersAsync.bind(this, callbackAsync), this.orderExpirationCheckingIntervalMs,
+            this.pruneExpiredOrders.bind(this, callback), this.orderExpirationCheckingIntervalMs,
        );
    }
    public unsubscribe(): void {
@@ -52,7 +52,7 @@ export class ExpirationWatcher {
        this.orderHashByExpirationRBTree.remove(orderHash);
        delete this.expiration[orderHash];
    }
-    private async pruneExpiredOrdersAsync(callbackAsync: (orderHash: string) => Promise<void>): Promise<void> {
+    private pruneExpiredOrders(callback: (orderHash: string) => void): void {
        const currentUnixTimestampMs = utils.getCurrentUnixTimestampMs();
        while (true) {
            const hasTrakedOrders = this.orderHashByExpirationRBTree.size === 0;
@@ -70,7 +70,7 @@ export class ExpirationWatcher {
            const orderHash = this.orderHashByExpirationRBTree.min();
            this.orderHashByExpirationRBTree.remove(orderHash);
            delete this.expiration[orderHash];
-            await callbackAsync(orderHash);
+            callback(orderHash);
        }
    }
 }
--- a/packages/0x.js/src/order_watcher/order_state_watcher.ts
+++ b/packages/0x.js/src/order_watcher/order_state_watcher.ts
@@ -1,42 +1,45 @@
-import * as _ from 'lodash';
 import {schemas} from '@0xproject/json-schemas';
+import {intervalUtils} from '@0xproject/utils';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
+import * as _ from 'lodash';
+
 import {ZeroEx} from '../0x';
-import {EventWatcher} from './event_watcher';
-import {assert} from '../utils/assert';
-import {utils} from '../utils/utils';
-import {artifacts} from '../artifacts';
-import {AbiDecoder} from '../utils/abi_decoder';
-import {intervalUtils} from '../utils/interval_utils';
-import {OrderStateUtils} from '../utils/order_state_utils';
-import {
-    LogEvent,
-    OrderState,
-    SignedOrder,
-    Web3Provider,
-    BlockParamLiteral,
-    LogWithDecodedArgs,
-    ContractEventArgs,
-    OnOrderStateChangeCallback,
-    OrderStateWatcherConfig,
-    ApprovalContractEventArgs,
-    TransferContractEventArgs,
-    LogFillContractEventArgs,
-    LogCancelContractEventArgs,
-    ExchangeEvents,
-    TokenEvents,
-    ZeroExError,
-    ExchangeContractErrs,
-} from '../types';
-import {Web3Wrapper} from '../web3_wrapper';
-import {TokenWrapper} from '../contract_wrappers/token_wrapper';
 import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
-import {OrderFilledCancelledLazyStore} from '../stores/order_filled_cancelled_lazy_store';
+import {TokenWrapper} from '../contract_wrappers/token_wrapper';
 import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
+import {OrderFilledCancelledLazyStore} from '../stores/order_filled_cancelled_lazy_store';
+import {
+    ApprovalContractEventArgs,
+    BlockParamLiteral,
+    ContractEventArgs,
+    DepositContractEventArgs,
+    EtherTokenEvents,
+    ExchangeContractErrs,
+    ExchangeEvents,
+    LogCancelContractEventArgs,
+    LogEvent,
+    LogFillContractEventArgs,
+    LogWithDecodedArgs,
+    OnOrderStateChangeCallback,
+    OrderState,
+    OrderStateWatcherConfig,
+    SignedOrder,
+    TokenEvents,
+    TransferContractEventArgs,
+    WithdrawalContractEventArgs,
+    ZeroExError,
+} from '../types';
+import {AbiDecoder} from '../utils/abi_decoder';
+import {assert} from '../utils/assert';
+import {OrderStateUtils} from '../utils/order_state_utils';
+import {utils} from '../utils/utils';
+
+import {EventWatcher} from './event_watcher';
 import {ExpirationWatcher} from './expiration_watcher';

 interface DependentOrderHashes {
    [makerAddress: string]: {
-        [makerToken: string]: Set<string>,
+        [makerToken: string]: Set<string>;
    };
 }

@@ -44,6 +47,12 @@ interface OrderByOrderHash {
    [orderHash: string]: SignedOrder;
 }

+interface OrderStateByOrderHash {
+    [orderHash: string]: OrderState;
+}
+
+const DEFAULT_CLEANUP_JOB_INTERVAL_MS = 1000 * 60 * 60; // 1h
+
 /**
 * This class includes all the functionality related to watching a set of orders
 * for potential changes in order validity/fillability. The orderWatcher notifies
@@ -51,6 +60,7 @@ interface OrderByOrderHash {
 * the order should be deemed invalid.
 */
 export class OrderStateWatcher {
+    private _orderStateByOrderHashCache: OrderStateByOrderHash = {};
    private _orderByOrderHash: OrderByOrderHash = {};
    private _dependentOrderHashes: DependentOrderHashes = {};
    private _callbackIfExists?: OnOrderStateChangeCallback;
@@ -61,6 +71,8 @@ export class OrderStateWatcher {
    private _orderStateUtils: OrderStateUtils;
    private _orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore;
    private _balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore;
+    private _cleanupJobInterval: number;
+    private _cleanupJobIntervalIdIfExists?: NodeJS.Timer;
    constructor(
        web3Wrapper: Web3Wrapper, abiDecoder: AbiDecoder, token: TokenWrapper, exchange: ExchangeWrapper,
        config?: OrderStateWatcherConfig,
@@ -69,7 +81,9 @@ export class OrderStateWatcher {
        this._web3Wrapper = web3Wrapper;
        const pollingIntervalIfExistsMs = _.isUndefined(config) ? undefined : config.eventPollingIntervalMs;
        this._eventWatcher = new EventWatcher(web3Wrapper, pollingIntervalIfExistsMs);
-        this._balanceAndProxyAllowanceLazyStore = new BalanceAndProxyAllowanceLazyStore(token);
+        this._balanceAndProxyAllowanceLazyStore = new BalanceAndProxyAllowanceLazyStore(
+            token, BlockParamLiteral.Pending,
+        );
        this._orderFilledCancelledLazyStore = new OrderFilledCancelledLazyStore(exchange);
        this._orderStateUtils = new OrderStateUtils(
            this._balanceAndProxyAllowanceLazyStore, this._orderFilledCancelledLazyStore,
@@ -83,18 +97,21 @@ export class OrderStateWatcher {
        this._expirationWatcher = new ExpirationWatcher(
            expirationMarginIfExistsMs, orderExpirationCheckingIntervalMsIfExists,
        );
+        this._cleanupJobInterval = _.isUndefined(config) || _.isUndefined(config.cleanupJobIntervalMs) ?
+                                   DEFAULT_CLEANUP_JOB_INTERVAL_MS :
+                                   config.cleanupJobIntervalMs;
    }
    /**
     * Add an order to the orderStateWatcher. Before the order is added, it's
     * signature is verified.
     * @param   signedOrder     The order you wish to start watching.
     */
-    public async addOrderAsync(signedOrder: SignedOrder): Promise<void> {
+    public addOrder(signedOrder: SignedOrder): void {
        assert.doesConformToSchema('signedOrder', signedOrder, schemas.signedOrderSchema);
        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
        assert.isValidSignature(orderHash, signedOrder.ecSignature, signedOrder.maker);
        this._orderByOrderHash[orderHash] = signedOrder;
-        await this.addToDependentOrderHashesAsync(signedOrder, orderHash);
+        this.addToDependentOrderHashes(signedOrder, orderHash);
        const expirationUnixTimestampMs = signedOrder.expirationUnixTimestampSec.times(1000);
        this._expirationWatcher.addOrder(orderHash, expirationUnixTimestampMs);
    }
@@ -102,15 +119,16 @@ export class OrderStateWatcher {
     * Removes an order from the orderStateWatcher
     * @param   orderHash     The orderHash of the order you wish to stop watching.
     */
-    public async removeOrderAsync(orderHash: string): Promise<void> {
+    public removeOrder(orderHash: string): void {
        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
        const signedOrder = this._orderByOrderHash[orderHash];
        if (_.isUndefined(signedOrder)) {
            return; // noop
        }
        delete this._orderByOrderHash[orderHash];
+        delete this._orderStateByOrderHashCache[orderHash];
        const exchange = (this._orderFilledCancelledLazyStore as any).exchange as ExchangeWrapper;
-        const zrxTokenAddress = await exchange.getZRXTokenAddressAsync();
+        const zrxTokenAddress = exchange.getZRXTokenAddress();
        this.removeFromDependentOrderHashes(signedOrder.maker, zrxTokenAddress, orderHash);
        this.removeFromDependentOrderHashes(signedOrder.maker, signedOrder.makerTokenAddress, orderHash);
        this._expirationWatcher.removeOrder(orderHash);
@@ -128,13 +146,16 @@ export class OrderStateWatcher {
        }
        this._callbackIfExists = callback;
        this._eventWatcher.subscribe(this._onEventWatcherCallbackAsync.bind(this));
-        this._expirationWatcher.subscribe(this._onOrderExpiredAsync.bind(this));
+        this._expirationWatcher.subscribe(this._onOrderExpired.bind(this));
+        this._cleanupJobIntervalIdIfExists = intervalUtils.setAsyncExcludingInterval(
+            this._cleanupAsync.bind(this), this._cleanupJobInterval,
+        );
    }
    /**
     * Ends an orderStateWatcher subscription.
     */
    public unsubscribe(): void {
-        if (_.isUndefined(this._callbackIfExists)) {
+        if (_.isUndefined(this._callbackIfExists) || _.isUndefined(this._cleanupJobIntervalIdIfExists)) {
            throw new Error(ZeroExError.SubscriptionNotFound);
        }
        this._balanceAndProxyAllowanceLazyStore.deleteAll();
@@ -142,15 +163,43 @@ export class OrderStateWatcher {
        delete this._callbackIfExists;
        this._eventWatcher.unsubscribe();
        this._expirationWatcher.unsubscribe();
+        intervalUtils.clearAsyncExcludingInterval(this._cleanupJobIntervalIdIfExists);
    }
-    private async _onOrderExpiredAsync(orderHash: string): Promise<void> {
+    private async _cleanupAsync(): Promise<void> {
+        for (const orderHash of _.keys(this._orderByOrderHash)) {
+            this._cleanupOrderRelatedState(orderHash);
+            await this._emitRevalidateOrdersAsync([orderHash]);
+        }
+    }
+    private _cleanupOrderRelatedState(orderHash: string): void {
+        const signedOrder = this._orderByOrderHash[orderHash];
+
+        this._orderFilledCancelledLazyStore.deleteFilledTakerAmount(orderHash);
+        this._orderFilledCancelledLazyStore.deleteCancelledTakerAmount(orderHash);
+
+        this._balanceAndProxyAllowanceLazyStore.deleteBalance(signedOrder.makerTokenAddress, signedOrder.maker);
+        this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(signedOrder.makerTokenAddress, signedOrder.maker);
+        this._balanceAndProxyAllowanceLazyStore.deleteBalance(signedOrder.takerTokenAddress, signedOrder.taker);
+        this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(signedOrder.takerTokenAddress, signedOrder.taker);
+
+        const zrxTokenAddress = this._getZRXTokenAddress();
+        if (!signedOrder.makerFee.isZero()) {
+            this._balanceAndProxyAllowanceLazyStore.deleteBalance(zrxTokenAddress, signedOrder.maker);
+            this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(zrxTokenAddress, signedOrder.maker);
+        }
+        if (!signedOrder.takerFee.isZero()) {
+            this._balanceAndProxyAllowanceLazyStore.deleteBalance(zrxTokenAddress, signedOrder.taker);
+            this._balanceAndProxyAllowanceLazyStore.deleteProxyAllowance(zrxTokenAddress, signedOrder.taker);
+        }
+    }
+    private _onOrderExpired(orderHash: string): void {
        const orderState: OrderState = {
            isValid: false,
            orderHash,
            error: ExchangeContractErrs.OrderFillExpired,
        };
        if (!_.isUndefined(this._orderByOrderHash[orderHash])) {
-            await this.removeOrderAsync(orderHash);
+            this.removeOrder(orderHash);
            if (!_.isUndefined(this._callbackIfExists)) {
                this._callbackIfExists(orderState);
            }
@@ -197,6 +246,36 @@ export class OrderStateWatcher {
                }
                break;
            }
+            case EtherTokenEvents.Deposit:
+            {
+                // Invalidate cache
+                const args = decodedLog.args as DepositContractEventArgs;
+                this._balanceAndProxyAllowanceLazyStore.deleteBalance(decodedLog.address, args._owner);
+                // Revalidate orders
+                makerToken = decodedLog.address;
+                makerAddress = args._owner;
+                if (!_.isUndefined(this._dependentOrderHashes[makerAddress]) &&
+                    !_.isUndefined(this._dependentOrderHashes[makerAddress][makerToken])) {
+                    const orderHashes = Array.from(this._dependentOrderHashes[makerAddress][makerToken]);
+                    await this._emitRevalidateOrdersAsync(orderHashes);
+                }
+                break;
+            }
+            case EtherTokenEvents.Withdrawal:
+            {
+                // Invalidate cache
+                const args = decodedLog.args as WithdrawalContractEventArgs;
+                this._balanceAndProxyAllowanceLazyStore.deleteBalance(decodedLog.address, args._owner);
+                // Revalidate orders
+                makerToken = decodedLog.address;
+                makerAddress = args._owner;
+                if (!_.isUndefined(this._dependentOrderHashes[makerAddress]) &&
+                    !_.isUndefined(this._dependentOrderHashes[makerAddress][makerToken])) {
+                    const orderHashes = Array.from(this._dependentOrderHashes[makerAddress][makerToken]);
+                    await this._emitRevalidateOrdersAsync(orderHashes);
+                }
+                break;
+            }
            case ExchangeEvents.LogFill:
            {
                // Invalidate cache
@@ -232,17 +311,23 @@ export class OrderStateWatcher {
    }
    private async _emitRevalidateOrdersAsync(orderHashes: string[]): Promise<void> {
        for (const orderHash of orderHashes) {
-            const signedOrder = this._orderByOrderHash[orderHash] as SignedOrder;
+            const signedOrder = this._orderByOrderHash[orderHash];
            // Most of these calls will never reach the network because the data is fetched from stores
            // and only updated when cache is invalidated
            const orderState = await this._orderStateUtils.getOrderStateAsync(signedOrder);
            if (_.isUndefined(this._callbackIfExists)) {
                break; // Unsubscribe was called
            }
+            if (_.isEqual(orderState, this._orderStateByOrderHashCache[orderHash])) {
+                // Actual order state didn't change
+                continue;
+            } else {
+                this._orderStateByOrderHashCache[orderHash] = orderState;
+            }
            this._callbackIfExists(orderState);
        }
    }
-    private async addToDependentOrderHashesAsync(signedOrder: SignedOrder, orderHash: string): Promise<void> {
+    private addToDependentOrderHashes(signedOrder: SignedOrder, orderHash: string): void {
        if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker])) {
            this._dependentOrderHashes[signedOrder.maker] = {};
        }
@@ -250,8 +335,7 @@ export class OrderStateWatcher {
            this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress] = new Set();
        }
        this._dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress].add(orderHash);
-        const exchange = (this._orderFilledCancelledLazyStore as any).exchange as ExchangeWrapper;
-        const zrxTokenAddress = await exchange.getZRXTokenAddressAsync();
+        const zrxTokenAddress = this._getZRXTokenAddress();
        if (_.isUndefined(this._dependentOrderHashes[signedOrder.maker][zrxTokenAddress])) {
            this._dependentOrderHashes[signedOrder.maker][zrxTokenAddress] = new Set();
        }
@@ -266,4 +350,9 @@ export class OrderStateWatcher {
            delete this._dependentOrderHashes[makerAddress];
        }
    }
+    private _getZRXTokenAddress(): string {
+        const exchange = (this._orderFilledCancelledLazyStore as any).exchange as ExchangeWrapper;
+        const zrxTokenAddress = exchange.getZRXTokenAddress();
+        return zrxTokenAddress;
+    }
 }
--- a/packages/0x.js/src/order_watcher/remaining_fillable_calculator.ts
+++ b/packages/0x.js/src/order_watcher/remaining_fillable_calculator.ts
@@ -0,0 +1,87 @@
+import {BigNumber} from 'bignumber.js';
+
+import {SignedOrder} from '../types';
+
+export class RemainingFillableCalculator {
+    private signedOrder: SignedOrder;
+    private isMakerTokenZRX: boolean;
+    // Transferrable Amount is the minimum of Approval and Balance
+    private transferrableMakerTokenAmount: BigNumber;
+    private transferrableMakerFeeTokenAmount: BigNumber;
+    private remainingMakerTokenAmount: BigNumber;
+    private remainingMakerFeeAmount: BigNumber;
+    constructor(signedOrder: SignedOrder,
+                isMakerTokenZRX: boolean,
+                transferrableMakerTokenAmount: BigNumber,
+                transferrableMakerFeeTokenAmount: BigNumber,
+                remainingMakerTokenAmount: BigNumber) {
+        this.signedOrder = signedOrder;
+        this.isMakerTokenZRX = isMakerTokenZRX;
+        this.transferrableMakerTokenAmount = transferrableMakerTokenAmount;
+        this.transferrableMakerFeeTokenAmount = transferrableMakerFeeTokenAmount;
+        this.remainingMakerTokenAmount = remainingMakerTokenAmount;
+        this.remainingMakerFeeAmount = remainingMakerTokenAmount.times(signedOrder.makerFee)
+                                                                .dividedToIntegerBy(signedOrder.makerTokenAmount);
+    }
+    public computeRemainingMakerFillable(): BigNumber {
+        if (this.hasSufficientFundsForFeeAndTransferAmount()) {
+            return this.remainingMakerTokenAmount;
+        }
+        if (this.signedOrder.makerFee.isZero()) {
+            return BigNumber.min(this.remainingMakerTokenAmount, this.transferrableMakerTokenAmount);
+        }
+        return this.calculatePartiallyFillableMakerTokenAmount();
+    }
+    public computeRemainingTakerFillable(): BigNumber {
+        return this.computeRemainingMakerFillable().times(this.signedOrder.takerTokenAmount)
+                                                   .dividedToIntegerBy(this.signedOrder.makerTokenAmount);
+    }
+    private hasSufficientFundsForFeeAndTransferAmount(): boolean {
+        if (this.isMakerTokenZRX) {
+            const totalZRXTransferAmountRequired = this.remainingMakerTokenAmount.plus(this.remainingMakerFeeAmount);
+            const hasSufficientFunds = this.transferrableMakerTokenAmount.greaterThanOrEqualTo(
+                                                                            totalZRXTransferAmountRequired);
+            return hasSufficientFunds;
+        } else {
+            const hasSufficientFundsForTransferAmount = this.transferrableMakerTokenAmount.greaterThanOrEqualTo(
+                                                            this.remainingMakerTokenAmount);
+            const hasSufficientFundsForFeeAmount = this.transferrableMakerFeeTokenAmount.greaterThanOrEqualTo(
+                                                       this.remainingMakerFeeAmount);
+            const hasSufficientFunds = hasSufficientFundsForTransferAmount && hasSufficientFundsForFeeAmount;
+            return hasSufficientFunds;
+        }
+    }
+    private calculatePartiallyFillableMakerTokenAmount(): BigNumber {
+        // Given an order for 200 wei for 2 ZRXwei fee, find 100 wei for 1 ZRXwei. Order ratio is then 100:1
+        const orderToFeeRatio = this.signedOrder.makerTokenAmount.dividedBy(this.signedOrder.makerFee);
+        // The number of times the maker can fill the order, if each fill only required the transfer of a single
+        // baseUnit of fee tokens.
+        // Given 2 ZRXwei, the maximum amount of times Maker can fill this order, in terms of fees, is 2
+        const fillableTimesInFeeTokenBaseUnits = BigNumber.min(this.transferrableMakerFeeTokenAmount,
+                                                               this.remainingMakerFeeAmount);
+        // The number of times the Maker can fill the order, given the Maker Token Balance
+        // Assuming a balance of 150 wei, and an orderToFeeRatio of 100:1, maker can fill this order 1 time.
+        let fillableTimesInMakerTokenUnits = this.transferrableMakerTokenAmount.dividedBy(orderToFeeRatio);
+        if (this.isMakerTokenZRX) {
+            // If ZRX is the maker token, the Fee and the Maker amount need to be removed from the same pool;
+            // 200 ZRXwei for 2ZRXwei fee can only be filled once (need 202 ZRXwei)
+            const totalZRXTokenPooled = this.transferrableMakerTokenAmount;
+            // The purchasing power here is less as the tokens are taken from the same Pool
+            // For every one number of fills, we have to take an extra ZRX out of the pool
+            fillableTimesInMakerTokenUnits = totalZRXTokenPooled.dividedBy(
+                                                                     orderToFeeRatio.plus(new BigNumber(1)));
+
+        }
+        // When Ratio is not fully divisible there can be remainders which cannot be represented, so they are floored.
+        // This can result in a RoundingError being thrown by the Exchange Contract.
+        const partiallyFillableMakerTokenAmount = fillableTimesInMakerTokenUnits
+                                                     .times(this.signedOrder.makerTokenAmount)
+                                                     .dividedToIntegerBy(this.signedOrder.makerFee);
+        const partiallyFillableFeeTokenAmount = fillableTimesInFeeTokenBaseUnits
+                                                     .times(this.signedOrder.makerTokenAmount)
+                                                     .dividedToIntegerBy(this.signedOrder.makerFee);
+        const partiallyFillableAmount = BigNumber.min(partiallyFillableMakerTokenAmount,
+                                                      partiallyFillableFeeTokenAmount);
+        return partiallyFillableAmount;
+    }
+}
--- a/packages/0x.js/src/schemas/zero_ex_config_schema.ts
+++ b/packages/0x.js/src/schemas/zero_ex_config_schema.ts
@@ -1,10 +1,13 @@
 export const zeroExConfigSchema = {
    id: '/ZeroExConfig',
    properties: {
+        networkId: {
+            type: 'number',
+            minimum: 0,
+        },
        gasPrice: {$ref: '/Number'},
        exchangeContractAddress: {$ref: '/Address'},
        tokenRegistryContractAddress: {$ref: '/Address'},
-        etherTokenContractAddress: {$ref: '/Address'},
        orderWatcherConfig: {
            type: 'object',
            properties: {
@@ -20,4 +23,5 @@ export const zeroExConfigSchema = {
        },
    },
    type: 'object',
+    required: ['networkId'],
 };
--- a/packages/0x.js/src/stores/balance_proxy_allowance_lazy_store.ts
+++ b/packages/0x.js/src/stores/balance_proxy_allowance_lazy_store.ts
@@ -1,6 +1,6 @@
-import * as _ from 'lodash';
-import * as Web3 from 'web3';
 import {BigNumber} from 'bignumber.js';
+import * as _ from 'lodash';
+
 import {TokenWrapper} from '../contract_wrappers/token_wrapper';
 import {BlockParamLiteral} from '../types';

@@ -9,25 +9,27 @@ import {BlockParamLiteral} from '../types';
 */
 export class BalanceAndProxyAllowanceLazyStore {
    private token: TokenWrapper;
+    private defaultBlock: BlockParamLiteral;
    private balance: {
        [tokenAddress: string]: {
-            [userAddress: string]: BigNumber,
-        },
+            [userAddress: string]: BigNumber;
+        };
    };
    private proxyAllowance: {
        [tokenAddress: string]: {
-            [userAddress: string]: BigNumber,
-        },
+            [userAddress: string]: BigNumber;
+        };
    };
-    constructor(token: TokenWrapper) {
+    constructor(token: TokenWrapper, defaultBlock: BlockParamLiteral) {
        this.token = token;
+        this.defaultBlock = defaultBlock;
        this.balance = {};
        this.proxyAllowance = {};
    }
    public async getBalanceAsync(tokenAddress: string, userAddress: string): Promise<BigNumber> {
        if (_.isUndefined(this.balance[tokenAddress]) || _.isUndefined(this.balance[tokenAddress][userAddress])) {
            const methodOpts = {
-                defaultBlock: BlockParamLiteral.Pending,
+                defaultBlock: this.defaultBlock,
            };
            const balance = await this.token.getBalanceAsync(tokenAddress, userAddress, methodOpts);
            this.setBalance(tokenAddress, userAddress, balance);
@@ -53,7 +55,7 @@ export class BalanceAndProxyAllowanceLazyStore {
        if (_.isUndefined(this.proxyAllowance[tokenAddress]) ||
            _.isUndefined(this.proxyAllowance[tokenAddress][userAddress])) {
            const methodOpts = {
-                defaultBlock: BlockParamLiteral.Pending,
+                defaultBlock: this.defaultBlock,
            };
            const proxyAllowance = await this.token.getProxyAllowanceAsync(tokenAddress, userAddress, methodOpts);
            this.setProxyAllowance(tokenAddress, userAddress, proxyAllowance);
--- a/packages/0x.js/src/stores/order_filled_cancelled_lazy_store.ts
+++ b/packages/0x.js/src/stores/order_filled_cancelled_lazy_store.ts
@@ -1,6 +1,6 @@
-import * as _ from 'lodash';
-import * as Web3 from 'web3';
 import {BigNumber} from 'bignumber.js';
+import * as _ from 'lodash';
+
 import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
 import {BlockParamLiteral} from '../types';

@@ -10,10 +10,10 @@ import {BlockParamLiteral} from '../types';
 export class OrderFilledCancelledLazyStore {
    private exchange: ExchangeWrapper;
    private filledTakerAmount: {
-        [orderHash: string]: BigNumber,
+        [orderHash: string]: BigNumber;
    };
    private cancelledTakerAmount: {
-        [orderHash: string]: BigNumber,
+        [orderHash: string]: BigNumber;
    };
    constructor(exchange: ExchangeWrapper) {
        this.exchange = exchange;
--- a/packages/0x.js/src/types.ts
+++ b/packages/0x.js/src/types.ts
@@ -1,9 +1,14 @@
-import * as Web3 from 'web3';
+import {TransactionReceipt} from '@0xproject/types';
 import BigNumber from 'bignumber.js';
+import * as Web3 from 'web3';

 export enum ZeroExError {
-    ContractDoesNotExist = 'CONTRACT_DOES_NOT_EXIST',
    ExchangeContractDoesNotExist = 'EXCHANGE_CONTRACT_DOES_NOT_EXIST',
+    ZRXContractDoesNotExist = 'ZRX_CONTRACT_DOES_NOT_EXIST',
+    EtherTokenContractDoesNotExist = 'ETHER_TOKEN_CONTRACT_DOES_NOT_EXIST',
+    TokenTransferProxyContractDoesNotExist = 'TOKEN_TRANSFER_PROXY_CONTRACT_DOES_NOT_EXIST',
+    TokenRegistryContractDoesNotExist = 'TOKEN_REGISTRY_CONTRACT_DOES_NOT_EXIST',
+    TokenContractDoesNotExist = 'TOKEN_CONTRACT_DOES_NOT_EXIST',
    UnhandledError = 'UNHANDLED_ERROR',
    UserHasNoAssociatedAddress = 'USER_HAS_NO_ASSOCIATED_ADDRESSES',
    InvalidSignature = 'INVALID_SIGNATURE',
@@ -23,6 +28,7 @@ export enum ZeroExError {
 export enum InternalZeroExError {
    NoAbiDecoder = 'NO_ABI_DECODER',
    ZrxNotInTokenRegistry = 'ZRX_NOT_IN_TOKEN_REGISTRY',
+    WethNotInTokenRegistry = 'WETH_NOT_IN_TOKEN_REGISTRY',
 }

 /**
@@ -40,161 +46,14 @@ export type OrderValues = [BigNumber, BigNumber, BigNumber,
                           BigNumber, BigNumber, BigNumber];

 export type LogEvent = Web3.LogEntryEvent;
-export type DecodedLogEvent<ArgsType> = Web3.DecodedLogEntryEvent<ArgsType>;
+export interface DecodedLogEvent<ArgsType> {
+    isRemoved: boolean;
+    log: LogWithDecodedArgs<ArgsType>;
+}

 export type EventCallback<ArgsType> = (err: null|Error, log?: DecodedLogEvent<ArgsType>) => void;
 export type EventWatcherCallback = (log: LogEvent) => void;

-export interface ExchangeContract extends Web3.ContractInstance {
-    isValidSignature: {
-        callAsync: (signerAddressHex: string, dataHex: string, v: number, r: string, s: string,
-                    txOpts?: TxOpts) => Promise<boolean>;
-    };
-    ZRX_TOKEN_CONTRACT: {
-        callAsync: () => Promise<string>;
-    };
-    TOKEN_TRANSFER_PROXY_CONTRACT: {
-        callAsync: () => Promise<string>;
-    };
-    getUnavailableTakerTokenAmount: {
-        callAsync: (orderHash: string, defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
-    };
-    isRoundingError: {
-        callAsync: (takerTokenFillAmount: BigNumber, takerTokenAmount: BigNumber,
-                    makerTokenAmount: BigNumber, txOpts?: TxOpts) => Promise<boolean>;
-    };
-    fillOrder: {
-        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                               fillTakerTokenAmount: BigNumber,
-                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                               v: number, r: string, s: string, txOpts?: TxOpts) => Promise<string>;
-        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                           fillTakerTokenAmount: BigNumber,
-                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                           v: number, r: string, s: string, txOpts?: TxOpts) => Promise<number>;
-    };
-    batchFillOrders: {
-        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                               fillTakerTokenAmounts: BigNumber[],
-                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                               v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<string>;
-        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                           fillTakerTokenAmounts: BigNumber[],
-                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
-    };
-    fillOrdersUpTo: {
-        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                               fillTakerTokenAmount: BigNumber,
-                               shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                               v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<string>;
-        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                           fillTakerTokenAmount: BigNumber,
-                           shouldThrowOnInsufficientBalanceOrAllowance: boolean,
-                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
-    };
-    cancelOrder: {
-        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                               cancelTakerTokenAmount: BigNumber, txOpts?: TxOpts) => Promise<string>;
-        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                           cancelTakerTokenAmount: BigNumber,
-                           txOpts?: TxOpts) => Promise<number>;
-    };
-    batchCancelOrders: {
-        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                               cancelTakerTokenAmounts: BigNumber[], txOpts?: TxOpts) => Promise<string>;
-        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                           cancelTakerTokenAmounts: BigNumber[],
-                           txOpts?: TxOpts) => Promise<number>;
-    };
-    fillOrKillOrder: {
-        sendTransactionAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                               fillTakerTokenAmount: BigNumber,
-                               v: number, r: string, s: string, txOpts?: TxOpts) => Promise<string>;
-        estimateGasAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues,
-                           fillTakerTokenAmount: BigNumber,
-                           v: number, r: string, s: string, txOpts?: TxOpts) => Promise<number>;
-    };
-    batchFillOrKillOrders: {
-        sendTransactionAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                               fillTakerTokenAmounts: BigNumber[],
-                               v: number[], r: string[], s: string[], txOpts: TxOpts) => Promise<string>;
-        estimateGasAsync: (orderAddresses: OrderAddresses[], orderValues: OrderValues[],
-                           fillTakerTokenAmounts: BigNumber[],
-                           v: number[], r: string[], s: string[], txOpts?: TxOpts) => Promise<number>;
-    };
-    filled: {
-        callAsync: (orderHash: string, defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
-    };
-    cancelled: {
-        callAsync: (orderHash: string, defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
-    };
-    getOrderHash: {
-        callAsync: (orderAddresses: OrderAddresses, orderValues: OrderValues) => Promise<string>;
-    };
-}
-
-export interface TokenContract extends Web3.ContractInstance {
-    balanceOf: {
-        callAsync: (address: string, defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
-    };
-    allowance: {
-        callAsync: (ownerAddress: string, allowedAddress: string,
-                    defaultBlock?: Web3.BlockParam) => Promise<BigNumber>;
-    };
-    transfer: {
-        sendTransactionAsync: (toAddress: string, amountInBaseUnits: BigNumber,
-                               txOpts?: TxOpts) => Promise<string>;
-    };
-    transferFrom: {
-        sendTransactionAsync: (fromAddress: string, toAddress: string, amountInBaseUnits: BigNumber,
-                               txOpts?: TxOpts) => Promise<string>;
-    };
-    approve: {
-        sendTransactionAsync: (proxyAddress: string, amountInBaseUnits: BigNumber,
-                               txOpts?: TxOpts) => Promise<string>;
-    };
-}
-
-export interface TokenRegistryContract extends Web3.ContractInstance {
-    getTokenMetaData: {
-        callAsync: (address: string) => Promise<TokenMetadata>;
-    };
-    getTokenAddresses: {
-        callAsync: () => Promise<string[]>;
-    };
-    getTokenAddressBySymbol: {
-        callAsync: (symbol: string) => Promise<string>;
-    };
-    getTokenAddressByName: {
-        callAsync: (name: string) => Promise<string>;
-    };
-    getTokenBySymbol: {
-        callAsync: (symbol: string) => Promise<TokenMetadata>;
-    };
-    getTokenByName: {
-        callAsync: (name: string) => Promise<TokenMetadata>;
-    };
-}
-
-export interface EtherTokenContract extends Web3.ContractInstance {
-    deposit: {
-        sendTransactionAsync: (txOpts: TxOpts) => Promise<string>;
-    };
-    withdraw: {
-        sendTransactionAsync: (amount: BigNumber, txOpts: TxOpts) => Promise<string>;
-    };
-}
-
-export interface TokenTransferProxyContract extends Web3.ContractInstance {
-    getAuthorizedAddresses: {
-        callAsync: () => Promise<string[]>;
-    };
-    authorized: {
-        callAsync: (address: string) => Promise<boolean>;
-    };
-}
-
 export enum SolidityTypes {
    Address = 'address',
    Uint256 = 'uint256',
@@ -288,8 +147,17 @@ export interface ApprovalContractEventArgs {
    _spender: string;
    _value: BigNumber;
 }
+export interface DepositContractEventArgs {
+    _owner: string;
+    _value: BigNumber;
+}
+export interface WithdrawalContractEventArgs {
+    _owner: string;
+    _value: BigNumber;
+}
 export type TokenContractEventArgs = TransferContractEventArgs|ApprovalContractEventArgs;
-export type ContractEventArgs = ExchangeContractEventArgs|TokenContractEventArgs;
+export type EtherTokenContractEventArgs = TokenContractEventArgs|DepositContractEventArgs|WithdrawalContractEventArgs;
+export type ContractEventArgs = ExchangeContractEventArgs|TokenContractEventArgs|EtherTokenContractEventArgs;
 export type ContractEventArg = string|BigNumber;

 export interface Order {
@@ -325,6 +193,7 @@ export interface TxOpts {
    from: string;
    gas?: number;
    value?: BigNumber;
+    gasPrice?: BigNumber;
 }

 export interface TokenAddressBySymbol {
@@ -342,21 +211,30 @@ export enum TokenEvents {
    Approval = 'Approval',
 }

-export type ContractEvents = TokenEvents|ExchangeEvents;
+export enum EtherTokenEvents  {
+    Transfer = 'Transfer',
+    Approval = 'Approval',
+    Deposit = 'Deposit',
+    Withdrawal = 'Withdrawal',
+}
+
+export type ContractEvents = TokenEvents|ExchangeEvents|EtherTokenEvents;

 export interface IndexedFilterValues {
    [index: string]: ContractEventArg;
 }

+// Earliest is omitted by design. It is simply an alias for the `0` constant and
+// is thus not very helpful. Moreover, this type is used in places that only accept
+// `latest` or `pending`.
 export enum BlockParamLiteral {
    Latest = 'latest',
-    Earliest = 'earliest',
    Pending = 'pending',
 }

 export type BlockParam = BlockParamLiteral|number;

-export interface SubscriptionOpts {
+export interface BlockRange {
    fromBlock: BlockParam;
    toBlock: BlockParam;
 }
@@ -374,18 +252,16 @@ export interface OrderFillRequest {
 }

 export type AsyncMethod = (...args: any[]) => Promise<any>;
+export type SyncMethod = (...args: any[]) => any;

 /**
 * We re-export the `Web3.Provider` type specified in the Web3 Typescript typings
 * since it is the type of the `provider` argument to the `ZeroEx` constructor.
- * It is however a `Web3` library type, not a native `0x.js` type.
+ * It is however a `Web3` library type, not a native `0x.js` type. To learn more
+ * about providers, visit https://0xproject.com/wiki#Web3-Provider-Explained
 */
 export type Web3Provider = Web3.Provider;

-export interface ExchangeContractByAddress {
-    [address: string]: ExchangeContract;
-}
-
 export interface JSONRPCPayload {
    params: any[];
    method: string;
@@ -396,25 +272,29 @@ export interface JSONRPCPayload {
 * eventPollingIntervalMs: How often to poll the Ethereum node for new events. Defaults: 200
 * expirationMarginMs: Amount of time before order expiry that you'd like to be notified
 * of an orders expiration. Defaults: 0
+ * cleanupJobIntervalMs: How often to run a cleanup job which revalidates all the orders. Defaults: 1h
 */
 export interface OrderStateWatcherConfig {
    orderExpirationCheckingIntervalMs?: number;
    eventPollingIntervalMs?: number;
    expirationMarginMs?: number;
+    cleanupJobIntervalMs?: number;
 }

 /*
+ * networkId: The id of the underlying ethereum network your provider is connected to. (1-mainnet, 42-kovan, 50-testrpc)
 * gasPrice: Gas price to use with every transaction
 * exchangeContractAddress: The address of an exchange contract to use
 * tokenRegistryContractAddress: The address of a token registry contract to use
- * etherTokenContractAddress: The address of an ether token contract to use
+ * tokenTransferProxyContractAddress: The address of the token transfer proxy contract to use
 * orderWatcherConfig: All the configs related to the orderWatcher
 */
 export interface ZeroExConfig {
-    gasPrice?: BigNumber; // Gas price to use with every transaction
+    networkId: number;
+    gasPrice?: BigNumber;
    exchangeContractAddress?: string;
    tokenRegistryContractAddress?: string;
-    etherTokenContractAddress?: string;
+    tokenTransferProxyContractAddress?: string;
    orderWatcherConfig?: OrderStateWatcherConfig;
 }

@@ -435,11 +315,16 @@ export interface TransactionReceiptWithDecodedLogs extends TransactionReceipt {
    logs: Array<LogWithDecodedArgs<DecodedLogArgs>|Web3.LogEntry>;
 }

+export type ArtifactContractName = 'ZRX'|'TokenTransferProxy'|'TokenRegistry'|'Token'|'Exchange'|'EtherToken';
+
 export interface Artifact {
-    abi: any;
-    networks: {[networkId: number]: {
-        address: string;
-    }};
+    contract_name: ArtifactContractName;
+    abi: Web3.ContractAbi;
+    networks: {
+        [networkId: number]: {
+            address: string;
+        };
+    };
 }

 /*
@@ -463,11 +348,20 @@ export interface MethodOpts {
 }

 /*
- * shouldValidate: Flag indicating whether the library should make attempts to validate a transaction before
- * broadcasting it. For example, order has a valid signature, maker has sufficient funds, etc.
+ * gasPrice: Gas price in Wei to use for a transaction
+ * gasLimit: The amount of gas to send with a transaction
 */
-export interface OrderTransactionOpts {
-    shouldValidate: boolean;
+export interface TransactionOpts {
+    gasPrice?: BigNumber;
+    gasLimit?: number;
+}
+
+/*
+ * shouldValidate: Flag indicating whether the library should make attempts to validate a transaction before
+ * broadcasting it. For example, order has a valid signature, maker has sufficient funds, etc. Default: true
+ */
+export interface OrderTransactionOpts extends TransactionOpts {
+    shouldValidate?: boolean;
 }

 export type FilterObject = Web3.FilterObject;
@@ -508,17 +402,4 @@ export interface OrderStateInvalid {
 export type OrderState = OrderStateValid|OrderStateInvalid;

 export type OnOrderStateChangeCallback = (orderState: OrderState) => void;
-
-export interface TransactionReceipt {
-    blockHash: string;
-    blockNumber: number;
-    transactionHash: string;
-    transactionIndex: number;
-    from: string;
-    to: string;
-    status: null|0|1;
-    cumulativeGasUsed: number;
-    gasUsed: number;
-    contractAddress: string|null;
-    logs: Web3.LogEntry[];
-}
+// tslint:disable:max-file-line-count
--- a/packages/0x.js/src/utils/abi_decoder.ts
+++ b/packages/0x.js/src/utils/abi_decoder.ts
@@ -1,12 +1,22 @@
-import * as Web3 from 'web3';
-import * as _ from 'lodash';
 import BigNumber from 'bignumber.js';
-import {AbiType, DecodedLogArgs, LogWithDecodedArgs, RawLog, SolidityTypes, ContractEventArgs} from '../types';
+import * as _ from 'lodash';
+import * as Web3 from 'web3';
 import * as SolidityCoder from 'web3/lib/solidity/coder';

+import {AbiType, ContractEventArgs, DecodedLogArgs, LogWithDecodedArgs, RawLog, SolidityTypes} from '../types';
+
 export class AbiDecoder {
    private savedABIs: Web3.AbiDefinition[] = [];
    private methodIds: {[signatureHash: string]: Web3.EventAbi} = {};
+    private static padZeros(address: string) {
+        let formatted = address;
+        if (_.startsWith(formatted, '0x')) {
+            formatted = formatted.slice(2);
+        }
+
+        formatted = _.padStart(formatted, 40, '0');
+        return `0x${formatted}`;
+    }
    constructor(abiArrays: Web3.AbiDefinition[][]) {
        _.map(abiArrays, this.addABI.bind(this));
    }
@@ -31,7 +41,7 @@ export class AbiDecoder {
            // Indexed parameters are stored in topics. Non-indexed ones in decodedData
            let value = param.indexed ? log.topics[topicsIndex++] : decodedData[dataIndex++];
            if (param.type === SolidityTypes.Address) {
-                value = this.padZeros(new BigNumber(value).toString(16));
+                value = AbiDecoder.padZeros(new BigNumber(value).toString(16));
            } else if (param.type === SolidityTypes.Uint256 ||
                       param.type === SolidityTypes.Uint8 ||
                       param.type === SolidityTypes.Uint) {
@@ -56,13 +66,4 @@ export class AbiDecoder {
        });
        this.savedABIs = this.savedABIs.concat(abiArray);
    }
-    private padZeros(address: string) {
-        let formatted = address;
-        if (_.startsWith(formatted, '0x')) {
-            formatted = formatted.slice(2);
-        }
-
-        formatted = _.padStart(formatted, 40, '0');
-        return `0x${formatted}`;
-    }
 }
--- a/packages/0x.js/src/utils/assert.ts
+++ b/packages/0x.js/src/utils/assert.ts
@@ -1,13 +1,14 @@
-import * as _ from 'lodash';
-import * as Web3 from 'web3';
-import BigNumber from 'bignumber.js';
-import {SchemaValidator, Schema} from '@0xproject/json-schemas';
 import {assert as sharedAssert} from '@0xproject/assert';
-import {Web3Wrapper} from '../web3_wrapper';
-import {signatureUtils} from '../utils/signature_utils';
-import {ECSignature} from '../types';
+// We need those two unused imports because they're actually used by sharedAssert which gets injected here
+// tslint:disable-next-line:no-unused-variable
+import {Schema} from '@0xproject/json-schemas';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
+// tslint:disable-next-line:no-unused-variable
+import * as BigNumber from 'bignumber.js';
+import * as _ from 'lodash';

-const HEX_REGEX = /^0x[0-9A-F]*$/i;
+import {ECSignature} from '../types';
+import {signatureUtils} from '../utils/signature_utils';

 export const assert = {
    ...sharedAssert,
--- a/packages/0x.js/src/utils/constants.ts
+++ b/packages/0x.js/src/utils/constants.ts
@@ -6,6 +6,7 @@ export const constants = {
    MAX_DIGITS_IN_UNSIGNED_256_INT: 78,
    INVALID_JUMP_PATTERN: 'invalid JUMP at',
    OUT_OF_GAS_PATTERN: 'out of gas',
+    INVALID_TAKER_FORMAT: 'instance.taker is not of a type(s) string',
    UNLIMITED_ALLOWANCE_IN_BASE_UNITS: new BigNumber(2).pow(256).minus(1),
    DEFAULT_BLOCK_POLLING_INTERVAL: 1000,
 };
--- a/packages/0x.js/src/utils/decorators.ts
+++ b/packages/0x.js/src/utils/decorators.ts
@@ -1,15 +1,37 @@
 import * as _ from 'lodash';
-import {constants} from './constants';
-import {AsyncMethod, ZeroExError} from '../types';

-export const decorators = {
-    /**
-     * Source: https://stackoverflow.com/a/29837695/3546986
-     */
-    contractCallErrorHandler(target: object,
-                             key: string|symbol,
-                             descriptor: TypedPropertyDescriptor<AsyncMethod>,
-    ): TypedPropertyDescriptor<AsyncMethod> {
+import {AsyncMethod, SyncMethod, ZeroExError} from '../types';
+
+import {constants} from './constants';
+
+type ErrorTransformer = (err: Error) => Error;
+
+const contractCallErrorTransformer = (error: Error) => {
+    if (_.includes(error.message, constants.INVALID_JUMP_PATTERN)) {
+        return new Error(ZeroExError.InvalidJump);
+    }
+    if (_.includes(error.message, constants.OUT_OF_GAS_PATTERN)) {
+        return new Error(ZeroExError.OutOfGas);
+    }
+    return error;
+};
+
+const schemaErrorTransformer = (error: Error) => {
+    if (_.includes(error.message, constants.INVALID_TAKER_FORMAT)) {
+        // tslint:disable-next-line:max-line-length
+        const errMsg = 'Order taker must be of type string. If you want anyone to be able to fill an order - pass ZeroEx.NULL_ADDRESS';
+        return new Error(errMsg);
+    }
+    return error;
+};
+
+/**
+ * Source: https://stackoverflow.com/a/29837695/3546986
+ */
+const asyncErrorHandlerFactory = (errorTransformer: ErrorTransformer) => {
+    const asyncErrorHandlingDecorator = (
+        target: object, key: string|symbol, descriptor: TypedPropertyDescriptor<AsyncMethod>,
+    ) => {
        const originalMethod = (descriptor.value as AsyncMethod);

        // Do not use arrow syntax here. Use a function expression in
@@ -20,16 +42,46 @@ export const decorators = {
                const result = await originalMethod.apply(this, args);
                return result;
            } catch (error) {
-                if (_.includes(error.message, constants.INVALID_JUMP_PATTERN)) {
-                    throw new Error(ZeroExError.InvalidJump);
-                }
-                if (_.includes(error.message, constants.OUT_OF_GAS_PATTERN)) {
-                    throw new Error(ZeroExError.OutOfGas);
-                }
-                throw error;
+                const transformedError = errorTransformer(error);
+                throw transformedError;
            }
        };

        return descriptor;
-    },
+    };
+
+    return asyncErrorHandlingDecorator;
+};
+
+const syncErrorHandlerFactory = (errorTransformer: ErrorTransformer) => {
+    const syncErrorHandlingDecorator = (
+        target: object, key: string|symbol, descriptor: TypedPropertyDescriptor<SyncMethod>,
+    ) => {
+        const originalMethod = (descriptor.value as SyncMethod);
+
+        // Do not use arrow syntax here. Use a function expression in
+        // order to use the correct value of `this` in this method
+        // tslint:disable-next-line:only-arrow-functions
+        descriptor.value = function(...args: any[]) {
+            try {
+                const result = originalMethod.apply(this, args);
+                return result;
+            } catch (error) {
+                const transformedError = errorTransformer(error);
+                throw transformedError;
+            }
+        };
+
+        return descriptor;
+    };
+
+    return syncErrorHandlingDecorator;
+};
+
+// _.flow(f, g) = f ∘ g
+const zeroExErrorTransformer = _.flow(schemaErrorTransformer, contractCallErrorTransformer);
+
+export const decorators = {
+    asyncZeroExErrorHandler: asyncErrorHandlerFactory(zeroExErrorTransformer),
+    syncZeroExErrorHandler: syncErrorHandlerFactory(zeroExErrorTransformer),
 };
--- a/packages/0x.js/src/utils/exchange_transfer_simulator.ts
+++ b/packages/0x.js/src/utils/exchange_transfer_simulator.ts
@@ -1,8 +1,9 @@
-import * as _ from 'lodash';
 import BigNumber from 'bignumber.js';
-import {ExchangeContractErrs, TradeSide, TransferType, BlockParamLiteral} from '../types';
+import * as _ from 'lodash';
+
 import {TokenWrapper} from '../contract_wrappers/token_wrapper';
 import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
+import {BlockParamLiteral, ExchangeContractErrs, TradeSide, TransferType} from '../types';

 enum FailureReason {
    Balance = 'balance',
@@ -35,8 +36,13 @@ const ERR_MSG_MAPPING = {
 export class ExchangeTransferSimulator {
    private store: BalanceAndProxyAllowanceLazyStore;
    private UNLIMITED_ALLOWANCE_IN_BASE_UNITS: BigNumber;
-    constructor(token: TokenWrapper) {
-        this.store = new BalanceAndProxyAllowanceLazyStore(token);
+    private static throwValidationError(failureReason: FailureReason, tradeSide: TradeSide,
+                                        transferType: TransferType): never {
+        const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
+        throw new Error(errMsg);
+    }
+    constructor(token: TokenWrapper, defaultBlock: BlockParamLiteral) {
+        this.store = new BalanceAndProxyAllowanceLazyStore(token, defaultBlock);
        this.UNLIMITED_ALLOWANCE_IN_BASE_UNITS = token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
    }
    /**
@@ -54,10 +60,10 @@ export class ExchangeTransferSimulator {
        const balance = await this.store.getBalanceAsync(tokenAddress, from);
        const proxyAllowance = await this.store.getProxyAllowanceAsync(tokenAddress, from);
        if (proxyAllowance.lessThan(amountInBaseUnits)) {
-            this.throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
+            ExchangeTransferSimulator.throwValidationError(FailureReason.ProxyAllowance, tradeSide, transferType);
        }
        if (balance.lessThan(amountInBaseUnits)) {
-            this.throwValidationError(FailureReason.Balance, tradeSide, transferType);
+            ExchangeTransferSimulator.throwValidationError(FailureReason.Balance, tradeSide, transferType);
        }
        await this.decreaseProxyAllowanceAsync(tokenAddress, from, amountInBaseUnits);
        await this.decreaseBalanceAsync(tokenAddress, from, amountInBaseUnits);
@@ -80,9 +86,4 @@ export class ExchangeTransferSimulator {
        const balance = await this.store.getBalanceAsync(tokenAddress, userAddress);
        this.store.setBalance(tokenAddress, userAddress, balance.minus(amountInBaseUnits));
    }
-    private throwValidationError(failureReason: FailureReason, tradeSide: TradeSide,
-                                 transferType: TransferType): Promise<never> {
-        const errMsg = ERR_MSG_MAPPING[failureReason][tradeSide][transferType];
-        throw new Error(errMsg);
-    }
 }
--- a/packages/0x.js/src/utils/filter_utils.ts
+++ b/packages/0x.js/src/utils/filter_utils.ts
@@ -1,9 +1,10 @@
-import * as _ from 'lodash';
-import * as Web3 from 'web3';
-import * as uuid from 'uuid/v4';
 import * as ethUtil from 'ethereumjs-util';
 import * as jsSHA3 from 'js-sha3';
-import {ContractEvents, IndexedFilterValues, SubscriptionOpts} from '../types';
+import * as _ from 'lodash';
+import * as uuid from 'uuid/v4';
+import * as Web3 from 'web3';
+
+import {BlockRange, ContractEvents, IndexedFilterValues} from '../types';

 const TOPIC_LENGTH = 32;

@@ -13,7 +14,7 @@ export const filterUtils = {
    },
    getFilter(address: string, eventName: ContractEvents,
              indexFilterValues: IndexedFilterValues, abi: Web3.ContractAbi,
-              subscriptionOpts?: SubscriptionOpts): Web3.FilterObject {
+              blockRange?: BlockRange): Web3.FilterObject {
        const eventAbi = _.find(abi, {name: eventName}) as Web3.EventAbi;
        const eventSignature = filterUtils.getEventSignatureFromAbiByName(eventAbi, eventName);
        const topicForEventSignature = ethUtil.addHexPrefix(jsSHA3.keccak256(eventSignature));
@@ -23,9 +24,9 @@ export const filterUtils = {
            address,
            topics,
        };
-        if (!_.isUndefined(subscriptionOpts)) {
+        if (!_.isUndefined(blockRange)) {
            filter = {
-                ...subscriptionOpts,
+                ...blockRange,
                ...filter,
            };
        }
--- a/packages/0x.js/src/utils/order_state_utils.ts
+++ b/packages/0x.js/src/utils/order_state_utils.ts
@@ -1,102 +1,26 @@
-import * as _ from 'lodash';
-import * as Web3 from 'web3';
 import BigNumber from 'bignumber.js';
+import * as _ from 'lodash';
+
+import {ZeroEx} from '../0x';
+import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
+import {RemainingFillableCalculator} from '../order_watcher/remaining_fillable_calculator';
+import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';
+import {OrderFilledCancelledLazyStore} from '../stores/order_filled_cancelled_lazy_store';
 import {
    ExchangeContractErrs,
-    SignedOrder,
    OrderRelevantState,
-    MethodOpts,
    OrderState,
-    OrderStateValid,
    OrderStateInvalid,
+    OrderStateValid,
+    SignedOrder,
 } from '../types';
-import {ZeroEx} from '../0x';
-import {TokenWrapper} from '../contract_wrappers/token_wrapper';
-import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
-import {utils} from '../utils/utils';
-import {constants} from '../utils/constants';
-import {OrderFilledCancelledLazyStore} from '../stores/order_filled_cancelled_lazy_store';
-import {BalanceAndProxyAllowanceLazyStore} from '../stores/balance_proxy_allowance_lazy_store';

 const ACCEPTABLE_RELATIVE_ROUNDING_ERROR = 0.0001;

 export class OrderStateUtils {
    private balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore;
    private orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore;
-    constructor(balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore,
-                orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore) {
-        this.balanceAndProxyAllowanceLazyStore = balanceAndProxyAllowanceLazyStore;
-        this.orderFilledCancelledLazyStore = orderFilledCancelledLazyStore;
-    }
-    public async getOrderStateAsync(signedOrder: SignedOrder): Promise<OrderState> {
-        const orderRelevantState = await this.getOrderRelevantStateAsync(signedOrder);
-        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-        try {
-            this.validateIfOrderIsValid(signedOrder, orderRelevantState);
-            const orderState: OrderStateValid = {
-                isValid: true,
-                orderHash,
-                orderRelevantState,
-            };
-            return orderState;
-        } catch (err) {
-            const orderState: OrderStateInvalid = {
-                isValid: false,
-                orderHash,
-                error: err.message,
-            };
-            return orderState;
-        }
-    }
-    public async getOrderRelevantStateAsync(signedOrder: SignedOrder): Promise<OrderRelevantState> {
-        // HACK: We access the private property here but otherwise the interface will be less nice.
-        // If we pass it from the instantiator - there is no opportunity to get it there
-        // because JS doesn't support async constructors.
-        // Moreover - it's cached under the hood so it's equivalent to an async constructor.
-        const exchange = (this.orderFilledCancelledLazyStore as any).exchange as ExchangeWrapper;
-        const zrxTokenAddress = await exchange.getZRXTokenAddressAsync();
-        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-        const makerBalance = await this.balanceAndProxyAllowanceLazyStore.getBalanceAsync(
-            signedOrder.makerTokenAddress, signedOrder.maker,
-        );
-        const makerProxyAllowance = await this.balanceAndProxyAllowanceLazyStore.getProxyAllowanceAsync(
-            signedOrder.makerTokenAddress, signedOrder.maker,
-        );
-        const makerFeeBalance = await this.balanceAndProxyAllowanceLazyStore.getBalanceAsync(
-            zrxTokenAddress, signedOrder.maker,
-        );
-        const makerFeeProxyAllowance = await this.balanceAndProxyAllowanceLazyStore.getProxyAllowanceAsync(
-            zrxTokenAddress, signedOrder.maker,
-        );
-        const filledTakerTokenAmount = await this.orderFilledCancelledLazyStore.getFilledTakerAmountAsync(orderHash);
-        const cancelledTakerTokenAmount = await this.orderFilledCancelledLazyStore.getCancelledTakerAmountAsync(
-            orderHash,
-        );
-        const unavailableTakerTokenAmount = await exchange.getUnavailableTakerAmountAsync(orderHash);
-        const totalMakerTokenAmount = signedOrder.makerTokenAmount;
-        const totalTakerTokenAmount = signedOrder.takerTokenAmount;
-        const remainingTakerTokenAmount = totalTakerTokenAmount.minus(unavailableTakerTokenAmount);
-        const remainingMakerTokenAmount = remainingTakerTokenAmount.times(totalMakerTokenAmount)
-                                                                   .dividedToIntegerBy(totalTakerTokenAmount);
-        const fillableMakerTokenAmount = BigNumber.min([makerProxyAllowance, makerBalance]);
-        const remainingFillableMakerTokenAmount = BigNumber.min(fillableMakerTokenAmount, remainingMakerTokenAmount);
-        const remainingFillableTakerTokenAmount = remainingFillableMakerTokenAmount
-                                                  .times(totalTakerTokenAmount)
-                                                  .dividedToIntegerBy(totalMakerTokenAmount);
-        // TODO: Handle edge case where maker token is ZRX with fee
-        const orderRelevantState = {
-            makerBalance,
-            makerProxyAllowance,
-            makerFeeBalance,
-            makerFeeProxyAllowance,
-            filledTakerTokenAmount,
-            cancelledTakerTokenAmount,
-            remainingFillableMakerTokenAmount,
-            remainingFillableTakerTokenAmount,
-        };
-        return orderRelevantState;
-    }
-    private validateIfOrderIsValid(signedOrder: SignedOrder, orderRelevantState: OrderRelevantState): void {
+    private static validateIfOrderIsValid(signedOrder: SignedOrder, orderRelevantState: OrderRelevantState): void {
        const unavailableTakerTokenAmount = orderRelevantState.cancelledTakerTokenAmount.add(
            orderRelevantState.filledTakerTokenAmount,
        );
@@ -126,7 +50,83 @@ export class OrderStateUtils {
            .lessThan(minFillableTakerTokenAmountWithinNoRoundingErrorRange)) {
            throw new Error(ExchangeContractErrs.OrderFillRoundingError);
        }
-        // TODO Add linear function solver when maker token is ZRX #badass
-        // Return the max amount that's fillable
+    }
+    constructor(balanceAndProxyAllowanceLazyStore: BalanceAndProxyAllowanceLazyStore,
+                orderFilledCancelledLazyStore: OrderFilledCancelledLazyStore) {
+        this.balanceAndProxyAllowanceLazyStore = balanceAndProxyAllowanceLazyStore;
+        this.orderFilledCancelledLazyStore = orderFilledCancelledLazyStore;
+    }
+    public async getOrderStateAsync(signedOrder: SignedOrder): Promise<OrderState> {
+        const orderRelevantState = await this.getOrderRelevantStateAsync(signedOrder);
+        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+        try {
+            OrderStateUtils.validateIfOrderIsValid(signedOrder, orderRelevantState);
+            const orderState: OrderStateValid = {
+                isValid: true,
+                orderHash,
+                orderRelevantState,
+            };
+            return orderState;
+        } catch (err) {
+            const orderState: OrderStateInvalid = {
+                isValid: false,
+                orderHash,
+                error: err.message,
+            };
+            return orderState;
+        }
+    }
+    public async getOrderRelevantStateAsync(signedOrder: SignedOrder): Promise<OrderRelevantState> {
+        // HACK: We access the private property here but otherwise the interface will be less nice.
+        // If we pass it from the instantiator - there is no opportunity to get it there
+        // because JS doesn't support async constructors.
+        // Moreover - it's cached under the hood so it's equivalent to an async constructor.
+        const exchange = (this.orderFilledCancelledLazyStore as any).exchange as ExchangeWrapper;
+        const zrxTokenAddress = exchange.getZRXTokenAddress();
+        const orderHash = ZeroEx.getOrderHashHex(signedOrder);
+        const makerBalance = await this.balanceAndProxyAllowanceLazyStore.getBalanceAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker,
+        );
+        const makerProxyAllowance = await this.balanceAndProxyAllowanceLazyStore.getProxyAllowanceAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker,
+        );
+        const makerFeeBalance = await this.balanceAndProxyAllowanceLazyStore.getBalanceAsync(
+            zrxTokenAddress, signedOrder.maker,
+        );
+        const makerFeeProxyAllowance = await this.balanceAndProxyAllowanceLazyStore.getProxyAllowanceAsync(
+            zrxTokenAddress, signedOrder.maker,
+        );
+        const filledTakerTokenAmount = await this.orderFilledCancelledLazyStore.getFilledTakerAmountAsync(orderHash);
+        const cancelledTakerTokenAmount = await this.orderFilledCancelledLazyStore.getCancelledTakerAmountAsync(
+            orderHash,
+        );
+        const unavailableTakerTokenAmount = await exchange.getUnavailableTakerAmountAsync(orderHash);
+        const totalMakerTokenAmount = signedOrder.makerTokenAmount;
+        const totalTakerTokenAmount = signedOrder.takerTokenAmount;
+        const remainingTakerTokenAmount = totalTakerTokenAmount.minus(unavailableTakerTokenAmount);
+        const remainingMakerTokenAmount = remainingTakerTokenAmount.times(totalMakerTokenAmount)
+                                                                   .dividedToIntegerBy(totalTakerTokenAmount);
+        const transferrableMakerTokenAmount = BigNumber.min([makerProxyAllowance, makerBalance]);
+        const transferrableFeeTokenAmount = BigNumber.min([makerFeeProxyAllowance, makerFeeBalance]);
+
+        const isMakerTokenZRX = signedOrder.makerTokenAddress === zrxTokenAddress;
+        const remainingFillableCalculator = new RemainingFillableCalculator(signedOrder,
+                                                isMakerTokenZRX,
+                                                transferrableMakerTokenAmount,
+                                                transferrableFeeTokenAmount,
+                                                remainingMakerTokenAmount);
+        const remainingFillableMakerTokenAmount = remainingFillableCalculator.computeRemainingMakerFillable();
+        const remainingFillableTakerTokenAmount = remainingFillableCalculator.computeRemainingTakerFillable();
+        const orderRelevantState = {
+            makerBalance,
+            makerProxyAllowance,
+            makerFeeBalance,
+            makerFeeProxyAllowance,
+            filledTakerTokenAmount,
+            cancelledTakerTokenAmount,
+            remainingFillableMakerTokenAmount,
+            remainingFillableTakerTokenAmount,
+        };
+        return orderRelevantState;
    }
 }
--- a/packages/0x.js/src/utils/order_validation_utils.ts
+++ b/packages/0x.js/src/utils/order_validation_utils.ts
@@ -1,18 +1,88 @@
-import * as _ from 'lodash';
 import BigNumber from 'bignumber.js';
-import {ExchangeContractErrs, SignedOrder, Order, ZeroExError, TradeSide, TransferType} from '../types';
+import * as _ from 'lodash';
+
 import {ZeroEx} from '../0x';
-import {TokenWrapper} from '../contract_wrappers/token_wrapper';
 import {ExchangeWrapper} from '../contract_wrappers/exchange_wrapper';
-import {utils} from '../utils/utils';
+import {ExchangeContractErrs, Order, SignedOrder, TradeSide, TransferType, ZeroExError} from '../types';
 import {constants} from '../utils/constants';
+import {utils} from '../utils/utils';
+
 import {ExchangeTransferSimulator} from './exchange_transfer_simulator';

 export class OrderValidationUtils {
-    private tokenWrapper: TokenWrapper;
    private exchangeWrapper: ExchangeWrapper;
-    constructor(tokenWrapper: TokenWrapper, exchangeWrapper: ExchangeWrapper) {
-        this.tokenWrapper = tokenWrapper;
+    public static validateCancelOrderThrowIfInvalid(
+        order: Order, cancelTakerTokenAmount: BigNumber, unavailableTakerTokenAmount: BigNumber,
+    ): void {
+        if (cancelTakerTokenAmount.eq(0)) {
+            throw new Error(ExchangeContractErrs.OrderCancelAmountZero);
+        }
+        if (order.takerTokenAmount.eq(unavailableTakerTokenAmount)) {
+            throw new Error(ExchangeContractErrs.OrderAlreadyCancelledOrFilled);
+        }
+        const currentUnixTimestampSec = utils.getCurrentUnixTimestampSec();
+        if (order.expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
+            throw new Error(ExchangeContractErrs.OrderCancelExpired);
+        }
+    }
+    public static async validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+        exchangeTradeEmulator: ExchangeTransferSimulator, signedOrder: SignedOrder,
+        fillTakerTokenAmount: BigNumber, senderAddress: string, zrxTokenAddress: string,
+    ): Promise<void> {
+        const fillMakerTokenAmount = OrderValidationUtils.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerTokenAmount,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            signedOrder.makerTokenAddress, signedOrder.maker, senderAddress, fillMakerTokenAmount,
+            TradeSide.Maker, TransferType.Trade,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            signedOrder.takerTokenAddress, senderAddress, signedOrder.maker, fillTakerTokenAmount,
+            TradeSide.Taker, TransferType.Trade,
+        );
+        const makerFeeAmount = OrderValidationUtils.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.makerFee,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            zrxTokenAddress, signedOrder.maker, signedOrder.feeRecipient, makerFeeAmount, TradeSide.Maker,
+            TransferType.Fee,
+        );
+        const takerFeeAmount = OrderValidationUtils.getPartialAmount(
+            fillTakerTokenAmount,
+            signedOrder.takerTokenAmount,
+            signedOrder.takerFee,
+        );
+        await exchangeTradeEmulator.transferFromAsync(
+            zrxTokenAddress, senderAddress, signedOrder.feeRecipient, takerFeeAmount, TradeSide.Taker,
+            TransferType.Fee,
+        );
+    }
+    private static validateRemainingFillAmountNotZeroOrThrow(
+        takerTokenAmount: BigNumber, unavailableTakerTokenAmount: BigNumber,
+    ) {
+        if (takerTokenAmount.eq(unavailableTakerTokenAmount)) {
+            throw new Error(ExchangeContractErrs.OrderRemainingFillAmountZero);
+        }
+    }
+    private static validateOrderNotExpiredOrThrow(expirationUnixTimestampSec: BigNumber) {
+        const currentUnixTimestampSec = utils.getCurrentUnixTimestampSec();
+        if (expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
+            throw new Error(ExchangeContractErrs.OrderFillExpired);
+        }
+    }
+    private static getPartialAmount(numerator: BigNumber, denominator: BigNumber,
+                                    target: BigNumber): BigNumber {
+        const fillMakerTokenAmount = numerator
+                                     .mul(target)
+                                     .div(denominator)
+                                     .round(0);
+        return fillMakerTokenAmount;
+    }
+    constructor(exchangeWrapper: ExchangeWrapper) {
        this.exchangeWrapper = exchangeWrapper;
    }
    public async validateOrderFillableOrThrowAsync(
@@ -20,15 +90,15 @@ export class OrderValidationUtils {
        expectedFillTakerTokenAmount?: BigNumber): Promise<void> {
        const orderHash = utils.getOrderHashHex(signedOrder);
        const unavailableTakerTokenAmount = await this.exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
-        this.validateRemainingFillAmountNotZeroOrThrow(
+        OrderValidationUtils.validateRemainingFillAmountNotZeroOrThrow(
            signedOrder.takerTokenAmount, unavailableTakerTokenAmount,
        );
-        this.validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
+        OrderValidationUtils.validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
        let fillTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
        if (!_.isUndefined(expectedFillTakerTokenAmount)) {
            fillTakerTokenAmount = expectedFillTakerTokenAmount;
        }
-        const fillMakerTokenAmount = this.getPartialAmount(
+        const fillMakerTokenAmount = OrderValidationUtils.getPartialAmount(
            fillTakerTokenAmount,
            signedOrder.takerTokenAmount,
            signedOrder.makerTokenAmount,
@@ -37,7 +107,7 @@ export class OrderValidationUtils {
            signedOrder.makerTokenAddress, signedOrder.maker, signedOrder.taker, fillMakerTokenAmount,
            TradeSide.Maker, TransferType.Trade,
        );
-        const makerFeeAmount = this.getPartialAmount(
+        const makerFeeAmount = OrderValidationUtils.getPartialAmount(
            fillTakerTokenAmount,
            signedOrder.takerTokenAmount,
            signedOrder.makerFee,
@@ -59,18 +129,18 @@ export class OrderValidationUtils {
            throw new Error(ZeroExError.InvalidSignature);
        }
        const unavailableTakerTokenAmount = await this.exchangeWrapper.getUnavailableTakerAmountAsync(orderHash);
-        this.validateRemainingFillAmountNotZeroOrThrow(
+        OrderValidationUtils.validateRemainingFillAmountNotZeroOrThrow(
            signedOrder.takerTokenAmount, unavailableTakerTokenAmount,
        );
        if (signedOrder.taker !== constants.NULL_ADDRESS && signedOrder.taker !== takerAddress) {
            throw new Error(ExchangeContractErrs.TransactionSenderIsNotFillOrderTaker);
        }
-        this.validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
+        OrderValidationUtils.validateOrderNotExpiredOrThrow(signedOrder.expirationUnixTimestampSec);
        const remainingTakerTokenAmount = signedOrder.takerTokenAmount.minus(unavailableTakerTokenAmount);
        const filledTakerTokenAmount = remainingTakerTokenAmount.lessThan(fillTakerTokenAmount) ?
                                       remainingTakerTokenAmount :
                                       fillTakerTokenAmount;
-        await this.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+        await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
            exchangeTradeEmulator, signedOrder, filledTakerTokenAmount, takerAddress, zrxTokenAddress,
        );

@@ -92,75 +162,4 @@ export class OrderValidationUtils {
            throw new Error(ExchangeContractErrs.InsufficientRemainingFillAmount);
        }
    }
-    public async validateCancelOrderThrowIfInvalidAsync(order: Order,
-                                                        cancelTakerTokenAmount: BigNumber,
-                                                        unavailableTakerTokenAmount: BigNumber,
-    ): Promise<void> {
-        if (cancelTakerTokenAmount.eq(0)) {
-            throw new Error(ExchangeContractErrs.OrderCancelAmountZero);
-        }
-        if (order.takerTokenAmount.eq(unavailableTakerTokenAmount)) {
-            throw new Error(ExchangeContractErrs.OrderAlreadyCancelledOrFilled);
-        }
-        const currentUnixTimestampSec = utils.getCurrentUnixTimestampSec();
-        if (order.expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
-            throw new Error(ExchangeContractErrs.OrderCancelExpired);
-        }
-    }
-    public async validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
-        exchangeTradeEmulator: ExchangeTransferSimulator, signedOrder: SignedOrder,
-        fillTakerTokenAmount: BigNumber, senderAddress: string, zrxTokenAddress: string): Promise<void> {
-        const fillMakerTokenAmount = this.getPartialAmount(
-            fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerTokenAmount,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            signedOrder.makerTokenAddress, signedOrder.maker, senderAddress, fillMakerTokenAmount,
-            TradeSide.Maker, TransferType.Trade,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            signedOrder.takerTokenAddress, senderAddress, signedOrder.maker, fillTakerTokenAmount,
-            TradeSide.Taker, TransferType.Trade,
-        );
-        const makerFeeAmount = this.getPartialAmount(
-            fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.makerFee,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            zrxTokenAddress, signedOrder.maker, signedOrder.feeRecipient, makerFeeAmount, TradeSide.Maker,
-            TransferType.Fee,
-        );
-        const takerFeeAmount = this.getPartialAmount(
-            fillTakerTokenAmount,
-            signedOrder.takerTokenAmount,
-            signedOrder.takerFee,
-        );
-        await exchangeTradeEmulator.transferFromAsync(
-            zrxTokenAddress, senderAddress, signedOrder.feeRecipient, takerFeeAmount, TradeSide.Taker,
-            TransferType.Fee,
-        );
-    }
-    private validateRemainingFillAmountNotZeroOrThrow(
-        takerTokenAmount: BigNumber, unavailableTakerTokenAmount: BigNumber,
-    ) {
-        if (takerTokenAmount.eq(unavailableTakerTokenAmount)) {
-            throw new Error(ExchangeContractErrs.OrderRemainingFillAmountZero);
-        }
-    }
-    private validateOrderNotExpiredOrThrow(expirationUnixTimestampSec: BigNumber) {
-        const currentUnixTimestampSec = utils.getCurrentUnixTimestampSec();
-        if (expirationUnixTimestampSec.lessThan(currentUnixTimestampSec)) {
-            throw new Error(ExchangeContractErrs.OrderFillExpired);
-        }
-    }
-    private getPartialAmount(numerator: BigNumber, denominator: BigNumber,
-                             target: BigNumber): BigNumber {
-        const fillMakerTokenAmount = numerator
-                                     .mul(target)
-                                     .div(denominator)
-                                     .round(0);
-        return fillMakerTokenAmount;
-    }
 }
--- a/packages/0x.js/src/utils/signature_utils.ts
+++ b/packages/0x.js/src/utils/signature_utils.ts
@@ -1,4 +1,5 @@
 import * as ethUtil from 'ethereumjs-util';
+
 import {ECSignature} from '../types';

 export const signatureUtils = {
--- a/packages/0x.js/src/utils/utils.ts
+++ b/packages/0x.js/src/utils/utils.ts
@@ -1,9 +1,10 @@
-import * as _ from 'lodash';
-import * as ethABI from 'ethereumjs-abi';
-import * as ethUtil from 'ethereumjs-util';
-import {Order, SignedOrder, SolidityTypes} from '../types';
 import BigNumber from 'bignumber.js';
 import BN = require('bn.js');
+import * as ethABI from 'ethereumjs-abi';
+import * as ethUtil from 'ethereumjs-util';
+import * as _ from 'lodash';
+
+import {Order, SignedOrder, SolidityTypes} from '../types';

 export const utils = {
    /**
--- a/packages/0x.js/test/0x.js_test.ts
+++ b/packages/0x.js/test/0x.js_test.ts
@@ -1,22 +1,27 @@
-import * as _ from 'lodash';
-import * as chai from 'chai';
-import {chaiSetup} from './utils/chai_setup';
-import 'mocha';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
 import BigNumber from 'bignumber.js';
+import * as chai from 'chai';
+import * as _ from 'lodash';
+import 'mocha';
 import * as Sinon from 'sinon';
-import {ZeroEx, Order, ZeroExError, LogWithDecodedArgs, ApprovalContractEventArgs, TokenEvents} from '../src';
+
+import {ApprovalContractEventArgs, LogWithDecodedArgs, Order, TokenEvents, ZeroEx} from '../src';
+
+import {chaiSetup} from './utils/chai_setup';
 import {constants} from './utils/constants';
 import {TokenUtils} from './utils/token_utils';
 import {web3Factory} from './utils/web3_factory';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';

-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);
 chaiSetup.configure();
 const expect = chai.expect;

 describe('ZeroEx library', () => {
    const web3 = web3Factory.create();
-    const zeroEx = new ZeroEx(web3.currentProvider);
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
+    const zeroEx = new ZeroEx(web3.currentProvider, config);
    describe('#setProvider', () => {
        it('overrides provider in nested web3s and invalidates contractInstances', async () => {
            // Instantiate the contract instances with the current provider
@@ -28,7 +33,7 @@ describe('ZeroEx library', () => {
            const newProvider = web3Factory.getRpcProvider();
            // Add property to newProvider so that we can differentiate it from old provider
            (newProvider as any).zeroExTestId = 1;
-            await zeroEx.setProviderAsync(newProvider);
+            zeroEx.setProvider(newProvider, constants.TESTRPC_NETWORK_ID);

            // Check that contractInstances with old provider are removed after provider update
            expect((zeroEx.exchange as any)._exchangeContractIfExists).to.be.undefined();
@@ -36,11 +41,11 @@ describe('ZeroEx library', () => {

            // Check that all nested web3 wrapper instances return the updated provider
            const nestedWeb3WrapperProvider = (zeroEx as any)._web3Wrapper.getCurrentProvider();
-            expect((nestedWeb3WrapperProvider as any).zeroExTestId).to.be.a('number');
+            expect((nestedWeb3WrapperProvider).zeroExTestId).to.be.a('number');
            const exchangeWeb3WrapperProvider = (zeroEx.exchange as any)._web3Wrapper.getCurrentProvider();
-            expect((exchangeWeb3WrapperProvider as any).zeroExTestId).to.be.a('number');
+            expect((exchangeWeb3WrapperProvider).zeroExTestId).to.be.a('number');
            const tokenRegistryWeb3WrapperProvider = (zeroEx.tokenRegistry as any)._web3Wrapper.getCurrentProvider();
-            expect((tokenRegistryWeb3WrapperProvider as any).zeroExTestId).to.be.a('number');
+            expect((tokenRegistryWeb3WrapperProvider).zeroExTestId).to.be.a('number');
        });
    });
    describe('#isValidSignature', () => {
@@ -77,9 +82,9 @@ describe('ZeroEx library', () => {
        it('should return true if the signature does pertain to the dataHex & address', async () => {
            const isValidSignatureLocal = ZeroEx.isValidSignature(dataHex, signature, address);
            expect(isValidSignatureLocal).to.be.true();
-            const isValidSignatureOnContract = await (zeroEx.exchange as any)
-                ._isValidSignatureUsingContractCallAsync(dataHex, signature, address);
-            return expect(isValidSignatureOnContract).to.be.true();
+            return expect(
+                (zeroEx.exchange as any)._isValidSignatureUsingContractCallAsync(dataHex, signature, address),
+            ).to.become(true);
        });
    });
    describe('#generateSalt', () => {
@@ -147,6 +152,15 @@ describe('ZeroEx library', () => {
            const orderHash = ZeroEx.getOrderHashHex(order);
            expect(orderHash).to.be.equal(expectedOrderHash);
        });
+        it('throws a readable error message if taker format is invalid', async () => {
+            const orderWithInvalidtakerFormat = {
+                ...order,
+                taker: null as any as string,
+            };
+            // tslint:disable-next-line:max-line-length
+            const expectedErrorMessage = 'Order taker must be of type string. If you want anyone to be able to fill an order - pass ZeroEx.NULL_ADDRESS';
+            expect(() => ZeroEx.getOrderHashHex(orderWithInvalidtakerFormat)).to.throw(expectedErrorMessage);
+        });
    });
    describe('#signOrderHashAsync', () => {
        let stubs: Sinon.SinonStub[] = [];
@@ -220,7 +234,7 @@ describe('ZeroEx library', () => {
            const tokens = await zeroEx.tokenRegistry.getTokensAsync();
            const tokenUtils = new TokenUtils(tokens);
            const zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
-            const proxyAddress = await zeroEx.proxy.getContractAddressAsync();
+            const proxyAddress = zeroEx.proxy.getContractAddress();
            const txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(zrxTokenAddress, coinbase);
            const txReceiptWithDecodedLogs = await zeroEx.awaitTransactionMinedAsync(txHash);
            const log = txReceiptWithDecodedLogs.logs[0] as LogWithDecodedArgs<ApprovalContractEventArgs>;
@@ -232,28 +246,21 @@ describe('ZeroEx library', () => {
    });
    describe('#config', () => {
        it('allows to specify exchange contract address', async () => {
-            const config = {
+            const zeroExConfig = {
                exchangeContractAddress: ZeroEx.NULL_ADDRESS,
+                networkId: constants.TESTRPC_NETWORK_ID,
            };
-            const zeroExWithWrongExchangeAddress = new ZeroEx(web3.currentProvider, config);
-            return expect(zeroExWithWrongExchangeAddress.exchange.getContractAddressAsync())
-                .to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
-        });
-        it('allows to specify ether token contract address', async () => {
-            const config = {
-                etherTokenContractAddress: ZeroEx.NULL_ADDRESS,
-            };
-            const zeroExWithWrongEtherTokenAddress = new ZeroEx(web3.currentProvider, config);
-            return expect(zeroExWithWrongEtherTokenAddress.etherToken.getContractAddressAsync())
-                .to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+            const zeroExWithWrongExchangeAddress = new ZeroEx(web3.currentProvider, zeroExConfig);
+            expect(zeroExWithWrongExchangeAddress.exchange.getContractAddress()).to.be.equal(ZeroEx.NULL_ADDRESS);
        });
        it('allows to specify token registry token contract address', async () => {
-            const config = {
+            const zeroExConfig = {
                tokenRegistryContractAddress: ZeroEx.NULL_ADDRESS,
+                networkId: constants.TESTRPC_NETWORK_ID,
            };
-            const zeroExWithWrongTokenRegistryAddress = new ZeroEx(web3.currentProvider, config);
-            return expect(zeroExWithWrongTokenRegistryAddress.tokenRegistry.getContractAddressAsync())
-                .to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+            const zeroExWithWrongTokenRegistryAddress = new ZeroEx(web3.currentProvider, zeroExConfig);
+            expect(zeroExWithWrongTokenRegistryAddress.tokenRegistry.getContractAddress())
+                .to.be.equal(ZeroEx.NULL_ADDRESS);
        });
    });
 });
--- a/packages/0x.js/test/artifacts_test.ts
+++ b/packages/0x.js/test/artifacts_test.ts
@@ -1,12 +1,12 @@
 import * as fs from 'fs';
-import * as chai from 'chai';
-import {chaiSetup} from './utils/chai_setup';
 import HDWalletProvider = require('truffle-hdwallet-provider');
+
 import {ZeroEx} from '../src';
+
+import {chaiSetup} from './utils/chai_setup';
 import {constants} from './utils/constants';

 chaiSetup.configure();
-const expect = chai.expect;

 // Those tests are slower cause they're talking to a remote node
 const TIMEOUT = 10000;
@@ -18,15 +18,18 @@ describe('Artifacts', () => {
        const packageJSON = JSON.parse(packageJSONContent);
        const mnemonic = packageJSON.config.mnemonic;
        const web3Provider = new HDWalletProvider(mnemonic, kovanRpcUrl);
-        const zeroEx = new ZeroEx(web3Provider);
+        const config = {
+            networkId: constants.KOVAN_NETWORK_ID,
+        };
+        const zeroEx = new ZeroEx(web3Provider, config);
        it('token registry contract is deployed', async () => {
            await (zeroEx.tokenRegistry as any)._getTokenRegistryContractAsync();
        }).timeout(TIMEOUT);
        it('proxy contract is deployed', async () => {
-            await (zeroEx.token as any)._getTokenTransferProxyAddressAsync();
+            await (zeroEx.proxy as any)._getTokenTransferProxyContractAsync();
        }).timeout(TIMEOUT);
        it('exchange contract is deployed', async () => {
-            await zeroEx.exchange.getContractAddressAsync();
+            await (zeroEx.exchange as any)._getExchangeContractAsync();
        }).timeout(TIMEOUT);
    });
    describe('contracts are deployed on ropsten', () => {
@@ -35,15 +38,18 @@ describe('Artifacts', () => {
        const packageJSON = JSON.parse(packageJSONContent);
        const mnemonic = packageJSON.config.mnemonic;
        const web3Provider = new HDWalletProvider(mnemonic, ropstenRpcUrl);
-        const zeroEx = new ZeroEx(web3Provider);
+        const config = {
+            networkId: constants.ROPSTEN_NETWORK_ID,
+        };
+        const zeroEx = new ZeroEx(web3Provider, config);
        it('token registry contract is deployed', async () => {
            await (zeroEx.tokenRegistry as any)._getTokenRegistryContractAsync();
        }).timeout(TIMEOUT);
        it('proxy contract is deployed', async () => {
-            await (zeroEx.token as any)._getTokenTransferProxyAddressAsync();
+            await (zeroEx.proxy as any)._getTokenTransferProxyContractAsync();
        }).timeout(TIMEOUT);
        it('exchange contract is deployed', async () => {
-            await zeroEx.exchange.getContractAddressAsync();
+            await (zeroEx.exchange as any)._getExchangeContractAsync();
        }).timeout(TIMEOUT);
    });
 });
--- a/packages/0x.js/test/assert_test.ts
+++ b/packages/0x.js/test/assert_test.ts
@@ -1,14 +1,20 @@
 import * as chai from 'chai';
 import 'mocha';
+
 import {ZeroEx} from '../src';
 import {assert} from '../src/utils/assert';
+
+import {constants} from './utils/constants';
 import {web3Factory} from './utils/web3_factory';

 const expect = chai.expect;

 describe('Assertion library', () => {
    const web3 = web3Factory.create();
-    const zeroEx = new ZeroEx(web3.currentProvider);
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
+    const zeroEx = new ZeroEx(web3.currentProvider, config);
    describe('#isSenderAddressHexAsync', () => {
        it('throws when address is invalid', async () => {
            const address = '0xdeadbeef';
--- a/packages/0x.js/test/ether_token_wrapper_test.ts
+++ b/packages/0x.js/test/ether_token_wrapper_test.ts
@@ -1,42 +1,69 @@
-import 'mocha';
-import * as chai from 'chai';
-import {chaiSetup} from './utils/chai_setup';
-import * as Web3 from 'web3';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
 import BigNumber from 'bignumber.js';
+import * as chai from 'chai';
+import 'mocha';
+import * as Web3 from 'web3';
+
+import {
+    ApprovalContractEventArgs,
+    BlockParamLiteral,
+    BlockRange,
+    DecodedLogEvent,
+    DepositContractEventArgs,
+    EtherTokenEvents,
+    Token,
+    TransferContractEventArgs,
+    WithdrawalContractEventArgs,
+    ZeroEx,
+    ZeroExError,
+} from '../src';
+import {artifacts} from '../src/artifacts';
+import {DoneCallback} from '../src/types';
+
+import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
+import {TokenUtils} from './utils/token_utils';
 import {web3Factory} from './utils/web3_factory';
-import {ZeroEx, ZeroExError} from '../src';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';

 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);

 // Since the address depositing/withdrawing ETH/WETH also needs to pay gas costs for the transaction,
 // a small amount of ETH will be used to pay this gas cost. We therefore check that the difference between
 // the expected balance and actual balance (given the amount of ETH deposited), only deviates by the amount
 // required to pay gas costs.
-const MAX_REASONABLE_GAS_COST_IN_WEI = 62237;
+const MAX_REASONABLE_GAS_COST_IN_WEI = 62517;

 describe('EtherTokenWrapper', () => {
    let web3: Web3;
    let zeroEx: ZeroEx;
+    let tokens: Token[];
    let userAddresses: string[];
    let addressWithETH: string;
    let wethContractAddress: string;
    let depositWeiAmount: BigNumber;
    let decimalPlaces: number;
+    let addressWithoutFunds: string;
    const gasPrice = new BigNumber(1);
    const zeroExConfig = {
        gasPrice,
+        networkId: constants.TESTRPC_NETWORK_ID,
    };
+    const transferAmount = new BigNumber(42);
+    const allowanceAmount = new BigNumber(42);
+    const depositAmount = new BigNumber(42);
+    const withdrawalAmount = new BigNumber(42);
    before(async () => {
        web3 = web3Factory.create();
        zeroEx = new ZeroEx(web3.currentProvider, zeroExConfig);
+        tokens = await zeroEx.tokenRegistry.getTokensAsync();
        userAddresses = await zeroEx.getAvailableAddressesAsync();
        addressWithETH = userAddresses[0];
-        wethContractAddress = await zeroEx.etherToken.getContractAddressAsync();
+        wethContractAddress = (zeroEx.etherToken as any)._getContractAddress(artifacts.EtherTokenArtifact);
        depositWeiAmount = (zeroEx as any)._web3Wrapper.toWei(new BigNumber(5));
        decimalPlaces = 7;
+        addressWithoutFunds = userAddresses[1];
    });
    beforeEach(async () => {
        await blockchainLifecycle.startAsync();
@@ -51,7 +78,7 @@ describe('EtherTokenWrapper', () => {
            expect(preETHBalance).to.be.bignumber.gt(0);
            expect(preWETHBalance).to.be.bignumber.equal(0);

-            const txHash = await zeroEx.etherToken.depositAsync(depositWeiAmount, addressWithETH);
+            const txHash = await zeroEx.etherToken.depositAsync(wethContractAddress, depositWeiAmount, addressWithETH);
            await zeroEx.awaitTransactionMinedAsync(txHash);

            const postETHBalanceInWei = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
@@ -69,7 +96,7 @@ describe('EtherTokenWrapper', () => {
            const overETHBalanceinWei = preETHBalance.add(extraETHBalance);

            return expect(
-                zeroEx.etherToken.depositAsync(overETHBalanceinWei, addressWithETH),
+                zeroEx.etherToken.depositAsync(wethContractAddress, overETHBalanceinWei, addressWithETH),
            ).to.be.rejectedWith(ZeroExError.InsufficientEthBalanceForDeposit);
        });
    });
@@ -77,7 +104,7 @@ describe('EtherTokenWrapper', () => {
        it('should successfully withdraw ETH in return for Wrapped ETH tokens', async () => {
            const ETHBalanceInWei = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);

-            await zeroEx.etherToken.depositAsync(depositWeiAmount, addressWithETH);
+            await zeroEx.etherToken.depositAsync(wethContractAddress, depositWeiAmount, addressWithETH);

            const expectedPreETHBalance = ETHBalanceInWei.minus(depositWeiAmount);
            const preETHBalance = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
@@ -86,7 +113,7 @@ describe('EtherTokenWrapper', () => {
            expect(gasCost).to.be.bignumber.lte(MAX_REASONABLE_GAS_COST_IN_WEI);
            expect(preWETHBalance).to.be.bignumber.equal(depositWeiAmount);

-            const txHash = await zeroEx.etherToken.withdrawAsync(depositWeiAmount, addressWithETH);
+            const txHash = await zeroEx.etherToken.withdrawAsync(wethContractAddress, depositWeiAmount, addressWithETH);
            await zeroEx.awaitTransactionMinedAsync(txHash);

            const postETHBalance = await (zeroEx as any)._web3Wrapper.getBalanceInWeiAsync(addressWithETH);
@@ -104,8 +131,213 @@ describe('EtherTokenWrapper', () => {
            const overWETHBalance = preWETHBalance.add(999999999);

            return expect(
-                zeroEx.etherToken.withdrawAsync(overWETHBalance, addressWithETH),
+                zeroEx.etherToken.withdrawAsync(wethContractAddress, overWETHBalance, addressWithETH),
            ).to.be.rejectedWith(ZeroExError.InsufficientWEthBalanceForWithdrawal);
        });
    });
+    describe('#subscribe', () => {
+        const indexFilterValues = {};
+        let etherTokenAddress: string;
+        before(() => {
+            const tokenUtils = new TokenUtils(tokens);
+            const etherToken = tokenUtils.getWethTokenOrThrow();
+            etherTokenAddress = etherToken.address;
+        });
+        afterEach(() => {
+            zeroEx.etherToken.unsubscribeAll();
+        });
+        // Hack: Mocha does not allow a test to be both async and have a `done` callback
+        // Since we need to await the receipt of the event in the `subscribe` callback,
+        // we do need both. A hack is to make the top-level async fn w/ a done callback and then
+        // wrap the rest of the test in an async block
+        // Source: https://github.com/mochajs/mocha/issues/2407
+        it('Should receive the Transfer event when tokens are transfered', (done: DoneCallback) => {
+            (async () => {
+                const callback = (err: Error, logEvent: DecodedLogEvent<TransferContractEventArgs>) => {
+                    expect(err).to.be.null();
+                    expect(logEvent).to.not.be.undefined();
+                    expect(logEvent.isRemoved).to.be.false();
+                    expect(logEvent.log.logIndex).to.be.equal(0);
+                    expect(logEvent.log.transactionIndex).to.be.equal(0);
+                    expect(logEvent.log.blockNumber).to.be.a('number');
+                    const args = logEvent.log.args;
+                    expect(args._from).to.be.equal(addressWithETH);
+                    expect(args._to).to.be.equal(addressWithoutFunds);
+                    expect(args._value).to.be.bignumber.equal(transferAmount);
+                    done();
+                };
+                await zeroEx.etherToken.depositAsync(etherTokenAddress, transferAmount, addressWithETH);
+                zeroEx.etherToken.subscribe(
+                    etherTokenAddress, EtherTokenEvents.Transfer, indexFilterValues, callback);
+                await zeroEx.token.transferAsync(
+                    etherTokenAddress, addressWithETH, addressWithoutFunds, transferAmount,
+                );
+            })().catch(done);
+        });
+        it('Should receive the Approval event when allowance is being set', (done: DoneCallback) => {
+            (async () => {
+                const callback = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                    expect(err).to.be.null();
+                    expect(logEvent).to.not.be.undefined();
+                    expect(logEvent.isRemoved).to.be.false();
+                    const args = logEvent.log.args;
+                    expect(args._owner).to.be.equal(addressWithETH);
+                    expect(args._spender).to.be.equal(addressWithoutFunds);
+                    expect(args._value).to.be.bignumber.equal(allowanceAmount);
+                    done();
+                };
+                zeroEx.etherToken.subscribe(
+                    etherTokenAddress, EtherTokenEvents.Approval, indexFilterValues, callback);
+                await zeroEx.token.setAllowanceAsync(
+                    etherTokenAddress, addressWithETH, addressWithoutFunds, allowanceAmount,
+                );
+            })().catch(done);
+        });
+        it('Should receive the Deposit event when ether is being deposited', (done: DoneCallback) => {
+            (async () => {
+                const callback = (err: Error, logEvent: DecodedLogEvent<DepositContractEventArgs>) => {
+                    expect(err).to.be.null();
+                    expect(logEvent).to.not.be.undefined();
+                    expect(logEvent.isRemoved).to.be.false();
+                    const args = logEvent.log.args;
+                    expect(args._owner).to.be.equal(addressWithETH);
+                    expect(args._value).to.be.bignumber.equal(depositAmount);
+                    done();
+                };
+                zeroEx.etherToken.subscribe(
+                    etherTokenAddress, EtherTokenEvents.Deposit, indexFilterValues, callback);
+                await zeroEx.etherToken.depositAsync(
+                    etherTokenAddress, depositAmount, addressWithETH,
+                );
+            })().catch(done);
+        });
+        it('Should receive the Withdrawal event when ether is being withdrawn', (done: DoneCallback) => {
+            (async () => {
+                const callback = (err: Error, logEvent: DecodedLogEvent<WithdrawalContractEventArgs>) => {
+                    expect(err).to.be.null();
+                    expect(logEvent).to.not.be.undefined();
+                    expect(logEvent.isRemoved).to.be.false();
+                    const args = logEvent.log.args;
+                    expect(args._owner).to.be.equal(addressWithETH);
+                    expect(args._value).to.be.bignumber.equal(depositAmount);
+                    done();
+                };
+                await zeroEx.etherToken.depositAsync(
+                    etherTokenAddress, depositAmount, addressWithETH,
+                );
+                zeroEx.etherToken.subscribe(
+                    etherTokenAddress, EtherTokenEvents.Withdrawal, indexFilterValues, callback);
+                await zeroEx.etherToken.withdrawAsync(
+                    etherTokenAddress, withdrawalAmount, addressWithETH,
+                );
+            })().catch(done);
+        });
+        it('should cancel outstanding subscriptions when ZeroEx.setProvider is called', (done: DoneCallback) => {
+            (async () => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                    done(new Error('Expected this subscription to have been cancelled'));
+                };
+                zeroEx.etherToken.subscribe(
+                    etherTokenAddress, EtherTokenEvents.Transfer, indexFilterValues, callbackNeverToBeCalled,
+                );
+                const callbackToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                    done();
+                };
+                const newProvider = web3Factory.getRpcProvider();
+                zeroEx.setProvider(newProvider, constants.TESTRPC_NETWORK_ID);
+                await zeroEx.etherToken.depositAsync(etherTokenAddress, transferAmount, addressWithETH);
+                zeroEx.etherToken.subscribe(
+                    etherTokenAddress, EtherTokenEvents.Transfer, indexFilterValues, callbackToBeCalled,
+                );
+                await zeroEx.token.transferAsync(
+                    etherTokenAddress, addressWithETH, addressWithoutFunds, transferAmount,
+                );
+            })().catch(done);
+        });
+        it('Should cancel subscription when unsubscribe called', (done: DoneCallback) => {
+            (async () => {
+                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                    done(new Error('Expected this subscription to have been cancelled'));
+                };
+                await zeroEx.etherToken.depositAsync(etherTokenAddress, transferAmount, addressWithETH);
+                const subscriptionToken = zeroEx.etherToken.subscribe(
+                    etherTokenAddress, EtherTokenEvents.Transfer, indexFilterValues, callbackNeverToBeCalled);
+                zeroEx.etherToken.unsubscribe(subscriptionToken);
+                await zeroEx.token.transferAsync(
+                    etherTokenAddress, addressWithETH, addressWithoutFunds, transferAmount,
+                );
+                done();
+            })().catch(done);
+        });
+    });
+    describe('#getLogsAsync', () => {
+        let etherTokenAddress: string;
+        let tokenTransferProxyAddress: string;
+        const blockRange: BlockRange = {
+            fromBlock: 0,
+            toBlock: BlockParamLiteral.Latest,
+        };
+        let txHash: string;
+        before(() => {
+            addressWithETH = userAddresses[0];
+            const tokenUtils = new TokenUtils(tokens);
+            const etherToken = tokenUtils.getWethTokenOrThrow();
+            etherTokenAddress = etherToken.address;
+            tokenTransferProxyAddress = zeroEx.proxy.getContractAddress();
+        });
+        it('should get logs with decoded args emitted by Approval', async () => {
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(etherTokenAddress, addressWithETH);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            const eventName = EtherTokenEvents.Approval;
+            const indexFilterValues = {};
+            const logs = await zeroEx.etherToken.getLogsAsync<ApprovalContractEventArgs>(
+                etherTokenAddress, eventName, blockRange, indexFilterValues,
+            );
+            expect(logs).to.have.length(1);
+            const args = logs[0].args;
+            expect(logs[0].event).to.be.equal(eventName);
+            expect(args._owner).to.be.equal(addressWithETH);
+            expect(args._spender).to.be.equal(tokenTransferProxyAddress);
+            expect(args._value).to.be.bignumber.equal(zeroEx.token.UNLIMITED_ALLOWANCE_IN_BASE_UNITS);
+        });
+        it('should get logs with decoded args emitted by Deposit', async () => {
+            await zeroEx.etherToken.depositAsync(etherTokenAddress, depositAmount, addressWithETH);
+            const eventName = EtherTokenEvents.Deposit;
+            const indexFilterValues = {};
+            const logs = await zeroEx.etherToken.getLogsAsync<DepositContractEventArgs>(
+                etherTokenAddress, eventName, blockRange, indexFilterValues,
+            );
+            expect(logs).to.have.length(1);
+            const args = logs[0].args;
+            expect(logs[0].event).to.be.equal(eventName);
+            expect(args._owner).to.be.equal(addressWithETH);
+            expect(args._value).to.be.bignumber.equal(depositAmount);
+        });
+        it('should only get the logs with the correct event name', async () => {
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(etherTokenAddress, addressWithETH);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            const differentEventName = EtherTokenEvents.Transfer;
+            const indexFilterValues = {};
+            const logs = await zeroEx.etherToken.getLogsAsync(
+                etherTokenAddress, differentEventName, blockRange, indexFilterValues,
+            );
+            expect(logs).to.have.length(0);
+        });
+        it('should only get the logs with the correct indexed fields', async () => {
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(etherTokenAddress, addressWithETH);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(etherTokenAddress, addressWithoutFunds);
+            await zeroEx.awaitTransactionMinedAsync(txHash);
+            const eventName = EtherTokenEvents.Approval;
+            const indexFilterValues = {
+                _owner: addressWithETH,
+            };
+            const logs = await zeroEx.etherToken.getLogsAsync<ApprovalContractEventArgs>(
+                etherTokenAddress, eventName, blockRange, indexFilterValues,
+            );
+            expect(logs).to.have.length(1);
+            const args = logs[0].args;
+            expect(args._owner).to.be.equal(addressWithETH);
+        });
+    });
 });
--- a/packages/0x.js/test/event_watcher_test.ts
+++ b/packages/0x.js/test/event_watcher_test.ts
@@ -1,19 +1,18 @@
-import 'mocha';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
 import * as chai from 'chai';
 import * as _ from 'lodash';
+import 'mocha';
 import * as Sinon from 'sinon';
 import * as Web3 from 'web3';
-import BigNumber from 'bignumber.js';
+
+import {
+    LogEvent,
+} from '../src';
+import {EventWatcher} from '../src/order_watcher/event_watcher';
+import {DoneCallback} from '../src/types';
+
 import {chaiSetup} from './utils/chai_setup';
 import {web3Factory} from './utils/web3_factory';
-import {Web3Wrapper} from '../src/web3_wrapper';
-import {EventWatcher} from '../src/order_watcher/event_watcher';
-import {
-    ZeroEx,
-    LogEvent,
-    DecodedLogEvent,
-} from '../src';
-import {DoneCallback} from '../src/types';

 chaiSetup.configure();
 const expect = chai.expect;
@@ -23,7 +22,6 @@ describe('EventWatcher', () => {
    let stubs: Sinon.SinonStub[] = [];
    let eventWatcher: EventWatcher;
    let web3Wrapper: Web3Wrapper;
-    const numConfirmations = 0;
    const logA: Web3.LogEntry = {
        address: '0x71d271f8b14adef568f8f28f1587ce7271ac4ca5',
        blockHash: null,
--- a/packages/0x.js/test/exchange_transfer_simulator_test.ts
+++ b/packages/0x.js/test/exchange_transfer_simulator_test.ts
@@ -1,19 +1,25 @@
-import * as chai from 'chai';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
 import BigNumber from 'bignumber.js';
-import {chaiSetup} from './utils/chai_setup';
-import {web3Factory} from './utils/web3_factory';
-import {ZeroEx, ExchangeContractErrs, Token} from '../src';
-import {TradeSide, TransferType} from '../src/types';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import * as chai from 'chai';
+
+import {ExchangeContractErrs, Token, ZeroEx} from '../src';
+import {BlockParamLiteral, TradeSide, TransferType} from '../src/types';
 import {ExchangeTransferSimulator} from '../src/utils/exchange_transfer_simulator';

+import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
+import {web3Factory} from './utils/web3_factory';
+
 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);

 describe('ExchangeTransferSimulator', () => {
    const web3 = web3Factory.create();
-    const zeroEx = new ZeroEx(web3.currentProvider);
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
+    const zeroEx = new ZeroEx(web3.currentProvider, config);
    const transferAmount = new BigNumber(5);
    let userAddresses: string[];
    let tokens: Token[];
@@ -37,7 +43,7 @@ describe('ExchangeTransferSimulator', () => {
    });
    describe('#transferFromAsync', () => {
        beforeEach(() => {
-            exchangeTransferSimulator = new ExchangeTransferSimulator(zeroEx.token);
+            exchangeTransferSimulator = new ExchangeTransferSimulator(zeroEx.token, BlockParamLiteral.Latest);
        });
        it('throws if the user doesn\'t have enough allowance', async () => {
            return expect(exchangeTransferSimulator.transferFromAsync(
--- a/packages/0x.js/test/exchange_wrapper_test.ts
+++ b/packages/0x.js/test/exchange_wrapper_test.ts
@@ -1,31 +1,33 @@
-import 'mocha';
-import * as chai from 'chai';
-import * as Web3 from 'web3';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
 import BigNumber from 'bignumber.js';
-import {chaiSetup} from './utils/chai_setup';
-import {web3Factory} from './utils/web3_factory';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import * as chai from 'chai';
+import 'mocha';
+import * as Web3 from 'web3';
+
 import {
-    ZeroEx,
-    Token,
-    SignedOrder,
-    SubscriptionOpts,
-    ExchangeEvents,
+    BlockRange,
+    DecodedLogEvent,
    ExchangeContractErrs,
+    ExchangeEvents,
+    LogCancelContractEventArgs,
+    LogFillContractEventArgs,
    OrderCancellationRequest,
    OrderFillRequest,
-    LogFillContractEventArgs,
-    LogCancelContractEventArgs,
-    LogEvent,
-    DecodedLogEvent,
+    SignedOrder,
+    Token,
+    ZeroEx,
 } from '../src';
-import {DoneCallback, BlockParamLiteral} from '../src/types';
+import {BlockParamLiteral, DoneCallback} from '../src/types';
+
+import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
 import {FillScenarios} from './utils/fill_scenarios';
 import {TokenUtils} from './utils/token_utils';
+import {web3Factory} from './utils/web3_factory';

 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);

 const NON_EXISTENT_ORDER_HASH = '0x79370342234e7acd6bbeac335bd3bb1d368383294b64b8160a00f4060e4d3777';

@@ -38,15 +40,19 @@ describe('ExchangeWrapper', () => {
    let zrxTokenAddress: string;
    let fillScenarios: FillScenarios;
    let exchangeContractAddress: string;
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
    before(async () => {
        web3 = web3Factory.create();
-        zeroEx = new ZeroEx(web3.currentProvider);
-        exchangeContractAddress = await zeroEx.exchange.getContractAddressAsync();
+        zeroEx = new ZeroEx(web3.currentProvider, config);
+        exchangeContractAddress = zeroEx.exchange.getContractAddress();
        userAddresses = await zeroEx.getAvailableAddressesAsync();
        tokens = await zeroEx.tokenRegistry.getTokensAsync();
        tokenUtils = new TokenUtils(tokens);
        zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens, zrxTokenAddress, exchangeContractAddress);
+        await fillScenarios.initTokenBalancesAsync();
    });
    beforeEach(async () => {
        await blockchainLifecycle.startAsync();
@@ -65,7 +71,7 @@ describe('ExchangeWrapper', () => {
        before(async () => {
            [coinbase, makerAddress, takerAddress, feeRecipient] = userAddresses;
            tokens = await zeroEx.tokenRegistry.getTokensAsync();
-            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            const [makerToken, takerToken] = tokenUtils.getDummyTokens();
            makerTokenAddress = makerToken.address;
            takerTokenAddress = takerToken.address;
        });
@@ -195,7 +201,7 @@ describe('ExchangeWrapper', () => {
        before(async () => {
            [coinbase, makerAddress, takerAddress, feeRecipient] = userAddresses;
            tokens = await zeroEx.tokenRegistry.getTokensAsync();
-            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            const [makerToken, takerToken] = tokenUtils.getDummyTokens();
            makerTokenAddress = makerToken.address;
            takerTokenAddress = takerToken.address;
        });
@@ -430,7 +436,7 @@ describe('ExchangeWrapper', () => {
        const cancelAmount = new BigNumber(3);
        beforeEach(async () => {
            [coinbase, makerAddress, takerAddress] = userAddresses;
-            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            const [makerToken, takerToken] = tokenUtils.getDummyTokens();
            makerTokenAddress = makerToken.address;
            takerTokenAddress = takerToken.address;
            signedOrder = await fillScenarios.createFillableSignedOrderAsync(
@@ -551,7 +557,8 @@ describe('ExchangeWrapper', () => {
        let orderHash: string;
        before(() => {
            takerAddress = userAddresses[1];
-            const [makerToken, takerToken] = tokens;
+            tokenUtils = new TokenUtils(tokens);
+            const [makerToken, takerToken] = tokenUtils.getDummyTokens();
            makerTokenAddress = makerToken.address;
            takerTokenAddress = takerToken.address;
        });
@@ -613,7 +620,7 @@ describe('ExchangeWrapper', () => {
            });
        });
    });
-    describe('#subscribeAsync', () => {
+    describe('#subscribe', () => {
        const indexFilterValues = {};
        const shouldThrowOnInsufficientBalanceOrAllowance = true;
        let makerTokenAddress: string;
@@ -627,7 +634,7 @@ describe('ExchangeWrapper', () => {
        const cancelTakerAmountInBaseUnits = new BigNumber(1);
        before(() => {
            [coinbase, makerAddress, takerAddress] = userAddresses;
-            const [makerToken, takerToken] = tokens;
+            const [makerToken, takerToken] = tokenUtils.getDummyTokens();
            makerTokenAddress = makerToken.address;
            takerTokenAddress = takerToken.address;
        });
@@ -649,10 +656,10 @@ describe('ExchangeWrapper', () => {
            (async () => {

                const callback = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
-                    expect(logEvent.event).to.be.equal(ExchangeEvents.LogFill);
+                    expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogFill);
                    done();
                };
-                await zeroEx.exchange.subscribeAsync(
+                zeroEx.exchange.subscribe(
                    ExchangeEvents.LogFill, indexFilterValues, callback,
                );
                await zeroEx.exchange.fillOrderAsync(
@@ -665,33 +672,33 @@ describe('ExchangeWrapper', () => {
            (async () => {

                const callback = (err: Error, logEvent: DecodedLogEvent<LogCancelContractEventArgs>) => {
-                    expect(logEvent.event).to.be.equal(ExchangeEvents.LogCancel);
+                    expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogCancel);
                    done();
                };
-                await zeroEx.exchange.subscribeAsync(
+                zeroEx.exchange.subscribe(
                    ExchangeEvents.LogCancel, indexFilterValues, callback,
                );
                await zeroEx.exchange.cancelOrderAsync(signedOrder, cancelTakerAmountInBaseUnits);
            })().catch(done);
        });
-        it('Outstanding subscriptions are cancelled when zeroEx.setProviderAsync called', (done: DoneCallback) => {
+        it('Outstanding subscriptions are cancelled when zeroEx.setProvider called', (done: DoneCallback) => {
            (async () => {

                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
                    done(new Error('Expected this subscription to have been cancelled'));
                };
-                await zeroEx.exchange.subscribeAsync(
+                zeroEx.exchange.subscribe(
                    ExchangeEvents.LogFill, indexFilterValues, callbackNeverToBeCalled,
                );

                const newProvider = web3Factory.getRpcProvider();
-                await zeroEx.setProviderAsync(newProvider);
+                zeroEx.setProvider(newProvider, constants.TESTRPC_NETWORK_ID);

                const callback = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
-                    expect(logEvent.event).to.be.equal(ExchangeEvents.LogFill);
+                    expect(logEvent.log.event).to.be.equal(ExchangeEvents.LogFill);
                    done();
                };
-                await zeroEx.exchange.subscribeAsync(
+                zeroEx.exchange.subscribe(
                    ExchangeEvents.LogFill, indexFilterValues, callback,
                );
                await zeroEx.exchange.fillOrderAsync(
@@ -705,7 +712,7 @@ describe('ExchangeWrapper', () => {
                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<LogFillContractEventArgs>) => {
                    done(new Error('Expected this subscription to have been cancelled'));
                };
-                const subscriptionToken = await zeroEx.exchange.subscribeAsync(
+                const subscriptionToken = zeroEx.exchange.subscribe(
                    ExchangeEvents.LogFill, indexFilterValues, callbackNeverToBeCalled,
                );
                zeroEx.exchange.unsubscribe(subscriptionToken);
@@ -725,7 +732,7 @@ describe('ExchangeWrapper', () => {
        const fillableAmount = new BigNumber(5);
        before(async () => {
            [, makerAddress, takerAddress] = userAddresses;
-            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            const [makerToken, takerToken] = tokenUtils.getDummyTokens();
            makerTokenAddress = makerToken.address;
            takerTokenAddress = takerToken.address;
        });
@@ -740,8 +747,8 @@ describe('ExchangeWrapper', () => {
        });
    });
    describe('#getZRXTokenAddressAsync', () => {
-        it('gets the same token as is in token registry', async () => {
-            const zrxAddress = await zeroEx.exchange.getZRXTokenAddressAsync();
+        it('gets the same token as is in token registry', () => {
+            const zrxAddress = zeroEx.exchange.getZRXTokenAddress();
            const zrxToken = tokenUtils.getProtocolTokenOrThrow();
            expect(zrxAddress).to.equal(zrxToken.address);
        });
@@ -753,14 +760,14 @@ describe('ExchangeWrapper', () => {
        let takerAddress: string;
        const fillableAmount = new BigNumber(5);
        const shouldThrowOnInsufficientBalanceOrAllowance = true;
-        const subscriptionOpts: SubscriptionOpts = {
-            fromBlock: BlockParamLiteral.Earliest,
+        const blockRange: BlockRange = {
+            fromBlock: 0,
            toBlock: BlockParamLiteral.Latest,
        };
        let txHash: string;
        before(async () => {
            [, makerAddress, takerAddress] = userAddresses;
-            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            const [makerToken, takerToken] = tokenUtils.getDummyTokens();
            makerTokenAddress = makerToken.address;
            takerTokenAddress = takerToken.address;
        });
@@ -774,7 +781,7 @@ describe('ExchangeWrapper', () => {
            await zeroEx.awaitTransactionMinedAsync(txHash);
            const eventName = ExchangeEvents.LogFill;
            const indexFilterValues = {};
-            const logs = await zeroEx.exchange.getLogsAsync(eventName, subscriptionOpts, indexFilterValues);
+            const logs = await zeroEx.exchange.getLogsAsync(eventName, blockRange, indexFilterValues);
            expect(logs).to.have.length(1);
            expect(logs[0].event).to.be.equal(eventName);
        });
@@ -788,7 +795,7 @@ describe('ExchangeWrapper', () => {
            await zeroEx.awaitTransactionMinedAsync(txHash);
            const differentEventName = ExchangeEvents.LogCancel;
            const indexFilterValues = {};
-            const logs = await zeroEx.exchange.getLogsAsync(differentEventName, subscriptionOpts, indexFilterValues);
+            const logs = await zeroEx.exchange.getLogsAsync(differentEventName, blockRange, indexFilterValues);
            expect(logs).to.have.length(0);
        });
        it('should only get the logs with the correct indexed fields', async () => {
@@ -814,11 +821,11 @@ describe('ExchangeWrapper', () => {
                maker: differentMakerAddress,
            };
            const logs = await zeroEx.exchange.getLogsAsync<LogFillContractEventArgs>(
-                eventName, subscriptionOpts, indexFilterValues,
+                eventName, blockRange, indexFilterValues,
            );
            expect(logs).to.have.length(1);
            const args = logs[0].args;
            expect(args.maker).to.be.equal(differentMakerAddress);
        });
    });
-});
+}); // tslint:disable:max-file-line-count
--- a/packages/0x.js/test/expiration_watcher_test.ts
+++ b/packages/0x.js/test/expiration_watcher_test.ts
@@ -1,24 +1,27 @@
-import 'mocha';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
+import BigNumber from 'bignumber.js';
 import * as chai from 'chai';
 import * as _ from 'lodash';
+import 'mocha';
 import * as Sinon from 'sinon';
 import * as Web3 from 'web3';
-import BigNumber from 'bignumber.js';
-import {chaiSetup} from './utils/chai_setup';
-import {web3Factory} from './utils/web3_factory';
-import {utils} from '../src/utils/utils';
-import {Web3Wrapper} from '../src/web3_wrapper';
-import {TokenUtils} from './utils/token_utils';
-import {ExpirationWatcher} from '../src/order_watcher/expiration_watcher';
-import {Token, DoneCallback} from '../src/types';
+
 import {ZeroEx} from '../src/0x';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {ExpirationWatcher} from '../src/order_watcher/expiration_watcher';
+import {DoneCallback, Token} from '../src/types';
+import {constants} from '../src/utils/constants';
+import {utils} from '../src/utils/utils';
+
+import {chaiSetup} from './utils/chai_setup';
+import {constants as testConstants} from './utils/constants';
 import {FillScenarios} from './utils/fill_scenarios';
 import {reportCallbackErrors} from './utils/report_callback_errors';
+import {TokenUtils} from './utils/token_utils';
+import {web3Factory} from './utils/web3_factory';

 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(testConstants.RPC_URL);

 describe('ExpirationWatcher', () => {
    let web3: Web3;
@@ -41,8 +44,11 @@ describe('ExpirationWatcher', () => {
    let expirationWatcher: ExpirationWatcher;
    before(async () => {
        web3 = web3Factory.create();
-        zeroEx = new ZeroEx(web3.currentProvider);
-        exchangeContractAddress = await zeroEx.exchange.getContractAddressAsync();
+        const config = {
+            networkId: constants.TESTRPC_NETWORK_ID,
+        };
+        zeroEx = new ZeroEx(web3.currentProvider, config);
+        exchangeContractAddress = zeroEx.exchange.getContractAddress();
        userAddresses = await zeroEx.getAvailableAddressesAsync();
        tokens = await zeroEx.tokenRegistry.getTokensAsync();
        tokenUtils = new TokenUtils(tokens);
@@ -50,7 +56,7 @@ describe('ExpirationWatcher', () => {
        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens, zrxTokenAddress, exchangeContractAddress);
        [coinbase, makerAddress, takerAddress, feeRecipient] = userAddresses;
        tokens = await zeroEx.tokenRegistry.getTokensAsync();
-        const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+        const [makerToken, takerToken] = tokenUtils.getDummyTokens();
        makerTokenAddress = makerToken.address;
        takerTokenAddress = takerToken.address;
    });
--- a/packages/0x.js/test/order_state_watcher_test.ts
+++ b/packages/0x.js/test/order_state_watcher_test.ts
@@ -1,36 +1,34 @@
-import 'mocha';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
+import BigNumber from 'bignumber.js';
 import * as chai from 'chai';
 import * as _ from 'lodash';
+import 'mocha';
 import * as Web3 from 'web3';
-import BigNumber from 'bignumber.js';
-import { chaiSetup } from './utils/chai_setup';
-import { web3Factory } from './utils/web3_factory';
-import { Web3Wrapper } from '../src/web3_wrapper';
-import { OrderStateWatcher } from '../src/order_watcher/order_state_watcher';
+
 import {
+    ExchangeContractErrs,
+    OrderState,
+    OrderStateInvalid,
+    OrderStateValid,
+    SignedOrder,
    Token,
    ZeroEx,
-    LogEvent,
-    DecodedLogEvent,
-    ZeroExConfig,
-    OrderState,
-    SignedOrder,
    ZeroExError,
-    OrderStateValid,
-    OrderStateInvalid,
-    ExchangeContractErrs,
 } from '../src';
-import { TokenUtils } from './utils/token_utils';
-import { FillScenarios } from './utils/fill_scenarios';
-import { DoneCallback } from '../src/types';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {DoneCallback} from '../src/types';
+
+import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
+import {FillScenarios} from './utils/fill_scenarios';
 import {reportCallbackErrors} from './utils/report_callback_errors';
+import {TokenUtils} from './utils/token_utils';
+import {web3Factory} from './utils/web3_factory';

 const TIMEOUT_MS = 150;

 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);

 describe('OrderStateWatcher', () => {
    let web3: Web3;
@@ -45,21 +43,24 @@ describe('OrderStateWatcher', () => {
    let takerToken: Token;
    let maker: string;
    let taker: string;
-    let web3Wrapper: Web3Wrapper;
    let signedOrder: SignedOrder;
-    const fillableAmount = ZeroEx.toBaseUnitAmount(new BigNumber(5), 18);
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
+    const decimals = constants.ZRX_DECIMALS;
+    const fillableAmount = ZeroEx.toBaseUnitAmount(new BigNumber(5), decimals);
    before(async () => {
        web3 = web3Factory.create();
-        zeroEx = new ZeroEx(web3.currentProvider);
-        exchangeContractAddress = await zeroEx.exchange.getContractAddressAsync();
+        zeroEx = new ZeroEx(web3.currentProvider, config);
+        exchangeContractAddress = zeroEx.exchange.getContractAddress();
        userAddresses = await zeroEx.getAvailableAddressesAsync();
        [, maker, taker] = userAddresses;
        tokens = await zeroEx.tokenRegistry.getTokensAsync();
        tokenUtils = new TokenUtils(tokens);
        zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens, zrxTokenAddress, exchangeContractAddress);
-        [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
-        web3Wrapper = (zeroEx as any)._web3Wrapper;
+        await fillScenarios.initTokenBalancesAsync();
+        [makerToken, takerToken] = tokenUtils.getDummyTokens();
    });
    beforeEach(async () => {
        await blockchainLifecycle.startAsync();
@@ -73,13 +74,13 @@ describe('OrderStateWatcher', () => {
                makerToken.address, takerToken.address, maker, taker, fillableAmount,
            );
            const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-            await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+            zeroEx.orderStateWatcher.addOrder(signedOrder);
            expect((zeroEx.orderStateWatcher as any)._orderByOrderHash).to.include({
                [orderHash]: signedOrder,
            });
            let dependentOrderHashes = (zeroEx.orderStateWatcher as any)._dependentOrderHashes;
            expect(dependentOrderHashes[signedOrder.maker][signedOrder.makerTokenAddress]).to.have.keys(orderHash);
-            await zeroEx.orderStateWatcher.removeOrderAsync(orderHash);
+            zeroEx.orderStateWatcher.removeOrder(orderHash);
            expect((zeroEx.orderStateWatcher as any)._orderByOrderHash).to.not.include({
                [orderHash]: signedOrder,
            });
@@ -92,7 +93,7 @@ describe('OrderStateWatcher', () => {
            );
            const orderHash = ZeroEx.getOrderHashHex(signedOrder);
            const nonExistentOrderHash = `0x${orderHash.substr(2).split('').reverse().join('')}`;
-            await zeroEx.orderStateWatcher.removeOrderAsync(nonExistentOrderHash);
+            zeroEx.orderStateWatcher.removeOrder(nonExistentOrderHash);
        });
    });
    describe('#subscribe', async () => {
@@ -109,7 +110,7 @@ describe('OrderStateWatcher', () => {
        afterEach(async () => {
            zeroEx.orderStateWatcher.unsubscribe();
            const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-            await zeroEx.orderStateWatcher.removeOrderAsync(orderHash);
+            zeroEx.orderStateWatcher.removeOrder(orderHash);
        });
        it('should emit orderStateInvalid when maker allowance set to 0 for watched order', (done: DoneCallback) => {
            (async () => {
@@ -117,7 +118,7 @@ describe('OrderStateWatcher', () => {
                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
                );
                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
                    expect(orderState.isValid).to.be.false();
                    const invalidOrderState = orderState as OrderStateInvalid;
@@ -134,8 +135,7 @@ describe('OrderStateWatcher', () => {
                signedOrder = await fillScenarios.createFillableSignedOrderAsync(
                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
                );
-                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
                    throw new Error('OrderState callback fired for irrelevant order');
                });
@@ -143,7 +143,6 @@ describe('OrderStateWatcher', () => {
                const notTheMaker = userAddresses[0];
                const anyRecipient = taker;
                const transferAmount = new BigNumber(2);
-                const notTheMakerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, notTheMaker);
                await zeroEx.token.transferAsync(makerToken.address, notTheMaker, anyRecipient, transferAmount);
                setTimeout(() => {
                    done();
@@ -156,7 +155,7 @@ describe('OrderStateWatcher', () => {
                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
                );
                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
                    expect(orderState.isValid).to.be.false();
                    const invalidOrderState = orderState as OrderStateInvalid;
@@ -176,18 +175,14 @@ describe('OrderStateWatcher', () => {
                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
                );
                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);

-                let eventCount = 0;
                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
-                    eventCount++;
                    expect(orderState.isValid).to.be.false();
                    const invalidOrderState = orderState as OrderStateInvalid;
                    expect(invalidOrderState.orderHash).to.be.equal(orderHash);
                    expect(invalidOrderState.error).to.be.equal(ExchangeContractErrs.OrderRemainingFillAmountZero);
-                    if (eventCount === 2) {
-                        done();
-                    }
+                    done();
                });
                zeroEx.orderStateWatcher.subscribe(callback);

@@ -204,15 +199,11 @@ describe('OrderStateWatcher', () => {
                );

                const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
-                const takerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, taker);
-
                const fillAmountInBaseUnits = new BigNumber(2);
                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);

-                let eventCount = 0;
                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
-                    eventCount++;
                    expect(orderState.isValid).to.be.true();
                    const validOrderState = orderState as OrderStateValid;
                    expect(validOrderState.orderHash).to.be.equal(orderHash);
@@ -224,9 +215,7 @@ describe('OrderStateWatcher', () => {
                    expect(orderRelevantState.remainingFillableTakerTokenAmount).to.be.bignumber.equal(
                        remainingFillable);
                    expect(orderRelevantState.makerBalance).to.be.bignumber.equal(remainingMakerBalance);
-                    if (eventCount === 2) {
-                        done();
-                    }
+                    done();
                });
                zeroEx.orderStateWatcher.subscribe(callback);
                const shouldThrowOnInsufficientBalanceOrAllowance = true;
@@ -242,11 +231,10 @@ describe('OrderStateWatcher', () => {
                signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
                    makerToken.address, takerToken.address, makerFee, takerFee, maker, taker, fillableAmount,
                    taker);
-                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
                    done();
                });
+                zeroEx.orderStateWatcher.addOrder(signedOrder);
                zeroEx.orderStateWatcher.subscribe(callback);
                await zeroEx.token.setProxyAllowanceAsync(zrxTokenAddress, maker, new BigNumber(0));
            })().catch(done);
@@ -254,31 +242,25 @@ describe('OrderStateWatcher', () => {
        describe('remainingFillable(M|T)akerTokenAmount', () => {
            it('should calculate correct remaining fillable', (done: DoneCallback) => {
                (async () => {
-                    const takerFillableAmount = ZeroEx.toBaseUnitAmount(new BigNumber(10), 18);
-                    const makerFillableAmount = ZeroEx.toBaseUnitAmount(new BigNumber(20), 18);
+                    const takerFillableAmount = ZeroEx.toBaseUnitAmount(new BigNumber(10), decimals);
+                    const makerFillableAmount = ZeroEx.toBaseUnitAmount(new BigNumber(20), decimals);
                    signedOrder = await fillScenarios.createAsymmetricFillableSignedOrderAsync(
                        makerToken.address, takerToken.address, maker, taker, makerFillableAmount,
                        takerFillableAmount,
                    );
-                    const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
-                    const takerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, taker);
-                    const fillAmountInBaseUnits = ZeroEx.toBaseUnitAmount(new BigNumber(2), 18);
+                    const fillAmountInBaseUnits = ZeroEx.toBaseUnitAmount(new BigNumber(2), decimals);
                    const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                    await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
-                    let eventCount = 0;
+                    zeroEx.orderStateWatcher.addOrder(signedOrder);
                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
-                        eventCount++;
                        expect(orderState.isValid).to.be.true();
                        const validOrderState = orderState as OrderStateValid;
                        expect(validOrderState.orderHash).to.be.equal(orderHash);
                        const orderRelevantState = validOrderState.orderRelevantState;
                        expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
-                            ZeroEx.toBaseUnitAmount(new BigNumber(16), 18));
+                            ZeroEx.toBaseUnitAmount(new BigNumber(16), decimals));
                        expect(orderRelevantState.remainingFillableTakerTokenAmount).to.be.bignumber.equal(
-                            ZeroEx.toBaseUnitAmount(new BigNumber(8), 18));
-                        if (eventCount === 2) {
-                            done();
-                        }
+                            ZeroEx.toBaseUnitAmount(new BigNumber(8), decimals));
+                        done();
                    });
                    zeroEx.orderStateWatcher.subscribe(callback);
                    const shouldThrowOnInsufficientBalanceOrAllowance = true;
@@ -293,10 +275,8 @@ describe('OrderStateWatcher', () => {
                        makerToken.address, takerToken.address, maker, taker, fillableAmount,
                    );

-                    const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
-
-                    const changedMakerApprovalAmount = ZeroEx.toBaseUnitAmount(new BigNumber(3), 18);
-                    await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                    const changedMakerApprovalAmount = ZeroEx.toBaseUnitAmount(new BigNumber(3), decimals);
+                    zeroEx.orderStateWatcher.addOrder(signedOrder);

                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
                        const validOrderState = orderState as OrderStateValid;
@@ -319,11 +299,12 @@ describe('OrderStateWatcher', () => {

                    const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);

-                    const remainingAmount = ZeroEx.toBaseUnitAmount(new BigNumber(1), 18);
+                    const remainingAmount = ZeroEx.toBaseUnitAmount(new BigNumber(1), decimals);
                    const transferAmount = makerBalance.sub(remainingAmount);
-                    await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                    zeroEx.orderStateWatcher.addOrder(signedOrder);

                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                        expect(orderState.isValid).to.be.true();
                        const validOrderState = orderState as OrderStateValid;
                        const orderRelevantState = validOrderState.orderRelevantState;
                        expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
@@ -337,6 +318,82 @@ describe('OrderStateWatcher', () => {
                        makerToken.address, maker, ZeroEx.NULL_ADDRESS, transferAmount);
                })().catch(done);
            });
+            it('should equal remaining amount when partially cancelled and order has fees', (done: DoneCallback) => {
+                (async () => {
+                    const takerFee = ZeroEx.toBaseUnitAmount(new BigNumber(0), decimals);
+                    const makerFee = ZeroEx.toBaseUnitAmount(new BigNumber(5), decimals);
+                    const feeRecipient = taker;
+                    signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                        makerToken.address, takerToken.address, makerFee, takerFee, maker,
+                        taker, fillableAmount, feeRecipient);
+
+                    const remainingTokenAmount = ZeroEx.toBaseUnitAmount(new BigNumber(4), decimals);
+                    const transferTokenAmount = makerFee.sub(remainingTokenAmount);
+                    zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                        expect(orderState.isValid).to.be.true();
+                        const validOrderState = orderState as OrderStateValid;
+                        const orderRelevantState = validOrderState.orderRelevantState;
+                        expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
+                            remainingTokenAmount);
+                        done();
+                    });
+                    zeroEx.orderStateWatcher.subscribe(callback);
+                    await zeroEx.exchange.cancelOrderAsync(signedOrder, transferTokenAmount);
+                })().catch(done);
+            });
+            it('should equal ratio amount when fee balance is lowered', (done: DoneCallback) => {
+                (async () => {
+                    const takerFee = ZeroEx.toBaseUnitAmount(new BigNumber(0), decimals);
+                    const makerFee = ZeroEx.toBaseUnitAmount(new BigNumber(5), decimals);
+                    const feeRecipient = taker;
+                    signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                        makerToken.address, takerToken.address, makerFee, takerFee, maker,
+                        taker, fillableAmount, feeRecipient);
+
+                    const remainingFeeAmount = ZeroEx.toBaseUnitAmount(new BigNumber(3), decimals);
+
+                    const remainingTokenAmount = ZeroEx.toBaseUnitAmount(new BigNumber(4), decimals);
+                    const transferTokenAmount = makerFee.sub(remainingTokenAmount);
+                    zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                        const validOrderState = orderState as OrderStateValid;
+                        const orderRelevantState = validOrderState.orderRelevantState;
+                        expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
+                            remainingFeeAmount);
+                        done();
+                    });
+                    zeroEx.orderStateWatcher.subscribe(callback);
+                    await zeroEx.token.setProxyAllowanceAsync(zrxTokenAddress, maker, remainingFeeAmount);
+                    await zeroEx.token.transferAsync(
+                        makerToken.address, maker, ZeroEx.NULL_ADDRESS, transferTokenAmount);
+                })().catch(done);
+            });
+            it('should calculate full amount when all available and non-divisible', (done: DoneCallback) => {
+                (async () => {
+                    const takerFee = ZeroEx.toBaseUnitAmount(new BigNumber(0), decimals);
+                    const makerFee = ZeroEx.toBaseUnitAmount(new BigNumber(2), decimals);
+                    const feeRecipient = taker;
+                    signedOrder = await fillScenarios.createFillableSignedOrderWithFeesAsync(
+                        makerToken.address, takerToken.address, makerFee, takerFee, maker,
+                        taker, fillableAmount, feeRecipient);
+
+                    zeroEx.orderStateWatcher.addOrder(signedOrder);
+
+                    const callback = reportCallbackErrors(done)((orderState: OrderState) => {
+                        const validOrderState = orderState as OrderStateValid;
+                        const orderRelevantState = validOrderState.orderRelevantState;
+                        expect(orderRelevantState.remainingFillableMakerTokenAmount).to.be.bignumber.equal(
+                            fillableAmount);
+                        done();
+                    });
+                    zeroEx.orderStateWatcher.subscribe(callback);
+                    await zeroEx.token.setProxyAllowanceAsync(
+                        makerToken.address, maker, ZeroEx.toBaseUnitAmount(new BigNumber(100), decimals));
+                })().catch(done);
+            });
        });
        it('should emit orderStateInvalid when watched order cancelled', (done: DoneCallback) => {
            (async () => {
@@ -344,7 +401,7 @@ describe('OrderStateWatcher', () => {
                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
                );
                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);

                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
                    expect(orderState.isValid).to.be.false();
@@ -355,7 +412,6 @@ describe('OrderStateWatcher', () => {
                });
                zeroEx.orderStateWatcher.subscribe(callback);

-                const shouldThrowOnInsufficientBalanceOrAllowance = true;
                await zeroEx.exchange.cancelOrderAsync(signedOrder, fillableAmount);
            })().catch(done);
        });
@@ -366,7 +422,7 @@ describe('OrderStateWatcher', () => {
                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
                );
                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);

                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
                    expect(orderState.isValid).to.be.false();
@@ -387,12 +443,9 @@ describe('OrderStateWatcher', () => {
                    makerToken.address, takerToken.address, maker, taker, fillableAmount,
                );

-                const makerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, maker);
-                const takerBalance = await zeroEx.token.getBalanceAsync(makerToken.address, taker);
-
                const cancelAmountInBaseUnits = new BigNumber(2);
                const orderHash = ZeroEx.getOrderHashHex(signedOrder);
-                await zeroEx.orderStateWatcher.addOrderAsync(signedOrder);
+                zeroEx.orderStateWatcher.addOrder(signedOrder);

                const callback = reportCallbackErrors(done)((orderState: OrderState) => {
                    expect(orderState.isValid).to.be.true();
@@ -407,4 +460,4 @@ describe('OrderStateWatcher', () => {
            })().catch(done);
        });
    });
-});
+}); // tslint:disable:max-file-line-count
--- a/packages/0x.js/test/order_validation_test.ts
+++ b/packages/0x.js/test/order_validation_test.ts
@@ -1,20 +1,23 @@
-import * as chai from 'chai';
-import * as Web3 from 'web3';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
 import BigNumber from 'bignumber.js';
+import * as chai from 'chai';
 import * as Sinon from 'sinon';
-import {chaiSetup} from './utils/chai_setup';
-import {web3Factory} from './utils/web3_factory';
-import {ZeroEx, SignedOrder, Token, ExchangeContractErrs, ZeroExError} from '../src';
-import {TradeSide, TransferType} from '../src/types';
-import {TokenUtils} from './utils/token_utils';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
-import {FillScenarios} from './utils/fill_scenarios';
-import {OrderValidationUtils} from '../src/utils/order_validation_utils';
+import * as Web3 from 'web3';
+
+import {ExchangeContractErrs, SignedOrder, Token, ZeroEx, ZeroExError} from '../src';
+import {BlockParamLiteral, TradeSide, TransferType} from '../src/types';
 import {ExchangeTransferSimulator} from '../src/utils/exchange_transfer_simulator';
+import {OrderValidationUtils} from '../src/utils/order_validation_utils';
+
+import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
+import {FillScenarios} from './utils/fill_scenarios';
+import {TokenUtils} from './utils/token_utils';
+import {web3Factory} from './utils/web3_factory';

 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);

 describe('OrderValidation', () => {
    let web3: Web3;
@@ -31,23 +34,24 @@ describe('OrderValidation', () => {
    let makerAddress: string;
    let takerAddress: string;
    let feeRecipient: string;
-    let orderValidationUtils: OrderValidationUtils;
    const fillableAmount = new BigNumber(5);
    const fillTakerAmount = new BigNumber(5);
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
    before(async () => {
        web3 = web3Factory.create();
-        zeroEx = new ZeroEx(web3.currentProvider);
-        exchangeContractAddress = await zeroEx.exchange.getContractAddressAsync();
+        zeroEx = new ZeroEx(web3.currentProvider, config);
+        exchangeContractAddress = zeroEx.exchange.getContractAddress();
        userAddresses = await zeroEx.getAvailableAddressesAsync();
        [coinbase, makerAddress, takerAddress, feeRecipient] = userAddresses;
        tokens = await zeroEx.tokenRegistry.getTokensAsync();
        tokenUtils = new TokenUtils(tokens);
        zrxTokenAddress = tokenUtils.getProtocolTokenOrThrow().address;
        fillScenarios = new FillScenarios(zeroEx, userAddresses, tokens, zrxTokenAddress, exchangeContractAddress);
-        const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+        const [makerToken, takerToken] = tokenUtils.getDummyTokens();
        makerTokenAddress = makerToken.address;
        takerTokenAddress = takerToken.address;
-        orderValidationUtils = new OrderValidationUtils(zeroEx.token, zeroEx.exchange);
    });
    beforeEach(async () => {
        await blockchainLifecycle.startAsync();
@@ -110,7 +114,7 @@ describe('OrderValidation', () => {
                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
            );
            // 27 <--> 28
-            signedOrder.ecSignature.v = 27 + (28 - signedOrder.ecSignature.v);
+            signedOrder.ecSignature.v = (28 - signedOrder.ecSignature.v) + 27;
            return expect(zeroEx.exchange.validateFillOrderThrowIfInvalidAsync(
                signedOrder, fillableAmount, takerAddress,
            )).to.be.rejectedWith(ZeroExError.InvalidSignature);
@@ -175,17 +179,15 @@ describe('OrderValidation', () => {
    });
    describe('validateCancelOrderAndThrowIfInvalidAsync', () => {
        let signedOrder: SignedOrder;
-        let orderHashHex: string;
        const cancelAmount = new BigNumber(3);
        beforeEach(async () => {
            [coinbase, makerAddress, takerAddress] = userAddresses;
-            const [makerToken, takerToken] = tokenUtils.getNonProtocolTokens();
+            const [makerToken, takerToken] = tokenUtils.getDummyTokens();
            makerTokenAddress = makerToken.address;
            takerTokenAddress = takerToken.address;
            signedOrder = await fillScenarios.createFillableSignedOrderAsync(
                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, fillableAmount,
            );
-            orderHashHex = ZeroEx.getOrderHashHex(signedOrder);
        });
        it('should throw when cancel amount is zero', async () => {
            const zeroCancelAmount = new BigNumber(0);
@@ -198,7 +200,6 @@ describe('OrderValidation', () => {
                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress,
                fillableAmount, expirationInPast,
            );
-            orderHashHex = ZeroEx.getOrderHashHex(expiredSignedOrder);
            return expect(zeroEx.exchange.validateCancelOrderThrowIfInvalidAsync(expiredSignedOrder, cancelAmount))
                .to.be.rejectedWith(ExchangeContractErrs.OrderCancelExpired);
        });
@@ -215,7 +216,7 @@ describe('OrderValidation', () => {
            return Sinon.match((value: BigNumber) => value.eq(expected));
        };
        beforeEach('create exchangeTransferSimulator', async () => {
-            exchangeTransferSimulator = new ExchangeTransferSimulator(zeroEx.token);
+            exchangeTransferSimulator = new ExchangeTransferSimulator(zeroEx.token, BlockParamLiteral.Latest);
            transferFromAsync = Sinon.spy();
            exchangeTransferSimulator.transferFromAsync = transferFromAsync as any;
        });
@@ -226,7 +227,7 @@ describe('OrderValidation', () => {
                makerTokenAddress, takerTokenAddress, makerFee, takerFee,
                makerAddress, takerAddress, fillableAmount, feeRecipient,
            );
-            await orderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+            await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
                exchangeTransferSimulator, signedOrder, fillableAmount, takerAddress, zrxTokenAddress,
            );
            expect(transferFromAsync.callCount).to.be.equal(4);
@@ -262,7 +263,7 @@ describe('OrderValidation', () => {
                makerTokenAddress, takerTokenAddress, makerFee, takerFee,
                makerAddress, ZeroEx.NULL_ADDRESS, fillableAmount, feeRecipient,
            );
-            await orderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+            await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
                exchangeTransferSimulator, signedOrder, fillableAmount, takerAddress, zrxTokenAddress,
            );
            expect(transferFromAsync.callCount).to.be.equal(4);
@@ -297,7 +298,7 @@ describe('OrderValidation', () => {
            const signedOrder = await fillScenarios.createAsymmetricFillableSignedOrderAsync(
                makerTokenAddress, takerTokenAddress, makerAddress, takerAddress, makerTokenAmount, takerTokenAmount,
            );
-            await orderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+            await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
                exchangeTransferSimulator, signedOrder, takerTokenAmount, takerAddress, zrxTokenAddress,
            );
            expect(transferFromAsync.callCount).to.be.equal(4);
@@ -312,7 +313,7 @@ describe('OrderValidation', () => {
                fillableAmount, ZeroEx.NULL_ADDRESS,
            );
            const fillTakerTokenAmount = fillableAmount.div(2).round(0);
-            await orderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
+            await OrderValidationUtils.validateFillOrderBalancesAllowancesThrowIfInvalidAsync(
                exchangeTransferSimulator, signedOrder, fillTakerTokenAmount, takerAddress, zrxTokenAddress,
            );
            const makerPartialFee = makerFee.div(2);
--- a/packages/0x.js/test/remaining_fillable_calculator_test.ts
+++ b/packages/0x.js/test/remaining_fillable_calculator_test.ts
@@ -0,0 +1,177 @@
+import BigNumber from 'bignumber.js';
+import * as chai from 'chai';
+import 'mocha';
+
+import {ZeroEx} from '../src/0x';
+import {RemainingFillableCalculator} from '../src/order_watcher/remaining_fillable_calculator';
+import {ECSignature, SignedOrder} from '../src/types';
+
+import {chaiSetup} from './utils/chai_setup';
+
+chaiSetup.configure();
+const expect = chai.expect;
+
+describe('RemainingFillableCalculator', () => {
+    let calculator: RemainingFillableCalculator;
+    let signedOrder: SignedOrder;
+    let transferrableMakerTokenAmount: BigNumber;
+    let transferrableMakerFeeTokenAmount: BigNumber;
+    let remainingMakerTokenAmount: BigNumber;
+    let makerAmount: BigNumber;
+    let takerAmount: BigNumber;
+    let makerFeeAmount: BigNumber;
+    let isMakerTokenZRX: boolean;
+    const makerToken: string = '0x1';
+    const takerToken: string = '0x2';
+    const decimals: number = 4;
+    const zero: BigNumber = new BigNumber(0);
+    const zeroAddress = '0x0';
+    const signature: ECSignature = {v: 27, r: '', s: ''};
+    beforeEach(async () => {
+        [makerAmount, takerAmount, makerFeeAmount] = [ZeroEx.toBaseUnitAmount(new BigNumber(50), decimals),
+                                                      ZeroEx.toBaseUnitAmount(new BigNumber(5), decimals),
+                                                      ZeroEx.toBaseUnitAmount(new BigNumber(1), decimals)];
+        [transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount] = [
+                                                ZeroEx.toBaseUnitAmount(new BigNumber(50), decimals),
+                                                ZeroEx.toBaseUnitAmount(new BigNumber(5), decimals)];
+    });
+    function buildSignedOrder(): SignedOrder {
+        return { ecSignature: signature,
+                 exchangeContractAddress: zeroAddress,
+                 feeRecipient: zeroAddress,
+                 maker: zeroAddress,
+                 taker: zeroAddress,
+                 makerFee: makerFeeAmount,
+                 takerFee: zero,
+                 makerTokenAmount: makerAmount,
+                 takerTokenAmount: takerAmount,
+                 makerTokenAddress: makerToken,
+                 takerTokenAddress: takerToken,
+                 salt: zero,
+                 expirationUnixTimestampSec: zero };
+    }
+    describe('Maker token is NOT ZRX', () => {
+        before(async () => {
+            isMakerTokenZRX = false;
+        });
+        it('calculates the correct amount when unfilled and funds available', () => {
+            signedOrder = buildSignedOrder();
+            remainingMakerTokenAmount = signedOrder.makerTokenAmount;
+            calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                           transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount, remainingMakerTokenAmount);
+            expect(calculator.computeRemainingMakerFillable()).to.be.bignumber.equal(remainingMakerTokenAmount);
+        });
+        it('calculates the correct amount when partially filled and funds available', () => {
+            signedOrder = buildSignedOrder();
+            remainingMakerTokenAmount = ZeroEx.toBaseUnitAmount(new BigNumber(1), decimals);
+            calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                           transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount, remainingMakerTokenAmount);
+            expect(calculator.computeRemainingMakerFillable()).to.be.bignumber.equal(remainingMakerTokenAmount);
+        });
+        it('calculates the amount to be 0 when all fee funds are transferred', () => {
+            signedOrder = buildSignedOrder();
+            transferrableMakerFeeTokenAmount = zero;
+            remainingMakerTokenAmount = signedOrder.makerTokenAmount;
+            calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                           transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount, remainingMakerTokenAmount);
+            expect(calculator.computeRemainingMakerFillable()).to.be.bignumber.equal(zero);
+        });
+        it('calculates the correct amount when balance is less than remaining fillable', () => {
+            signedOrder = buildSignedOrder();
+            const partiallyFilledAmount = ZeroEx.toBaseUnitAmount(new BigNumber(2), decimals);
+            remainingMakerTokenAmount = signedOrder.makerTokenAmount.minus(partiallyFilledAmount);
+            transferrableMakerTokenAmount = remainingMakerTokenAmount.minus(partiallyFilledAmount);
+            calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                           transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount, remainingMakerTokenAmount);
+            expect(calculator.computeRemainingMakerFillable()).to.be.bignumber.equal(transferrableMakerTokenAmount);
+        });
+        describe('Order to Fee Ratio is < 1', () => {
+            beforeEach(async () => {
+                [makerAmount, takerAmount, makerFeeAmount] = [ZeroEx.toBaseUnitAmount(new BigNumber(3), decimals),
+                                                              ZeroEx.toBaseUnitAmount(new BigNumber(6), decimals),
+                                                              ZeroEx.toBaseUnitAmount(new BigNumber(6), decimals)];
+            });
+            it('calculates the correct amount when funds unavailable', () => {
+                signedOrder = buildSignedOrder();
+                remainingMakerTokenAmount = signedOrder.makerTokenAmount;
+                const transferredAmount = ZeroEx.toBaseUnitAmount(new BigNumber(2), decimals);
+                transferrableMakerTokenAmount = remainingMakerTokenAmount.minus(transferredAmount);
+                calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                                 transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount,
+                                 remainingMakerTokenAmount);
+                expect(calculator.computeRemainingMakerFillable()).to.be.bignumber.equal(transferrableMakerTokenAmount);
+            });
+        });
+        describe('Ratio is not evenly divisble', () => {
+            beforeEach(async () => {
+                [makerAmount, takerAmount, makerFeeAmount] = [ZeroEx.toBaseUnitAmount(new BigNumber(3), decimals),
+                                                              ZeroEx.toBaseUnitAmount(new BigNumber(7), decimals),
+                                                              ZeroEx.toBaseUnitAmount(new BigNumber(7), decimals)];
+            });
+            it('calculates the correct amount when funds unavailable', () => {
+                signedOrder = buildSignedOrder();
+                remainingMakerTokenAmount = signedOrder.makerTokenAmount;
+                const transferredAmount = ZeroEx.toBaseUnitAmount(new BigNumber(2), decimals);
+                transferrableMakerTokenAmount = remainingMakerTokenAmount.minus(transferredAmount);
+                calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                                 transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount,
+                                 remainingMakerTokenAmount);
+                const calculatedFillableAmount = calculator.computeRemainingMakerFillable();
+                expect(calculatedFillableAmount.lessThanOrEqualTo(transferrableMakerTokenAmount)).to.be.true();
+                expect(calculatedFillableAmount).to.be.bignumber.greaterThan(new BigNumber(0));
+                const orderToFeeRatio = signedOrder.makerTokenAmount.dividedBy(signedOrder.makerFee);
+                const calculatedFeeAmount = calculatedFillableAmount.dividedBy(orderToFeeRatio);
+                expect(calculatedFeeAmount).to.be.bignumber.lessThan(transferrableMakerFeeTokenAmount);
+            });
+        });
+    });
+    describe('Maker Token is ZRX', () => {
+        before(async () => {
+            isMakerTokenZRX = true;
+        });
+        it('calculates the correct amount when unfilled and funds available', () => {
+            signedOrder = buildSignedOrder();
+            transferrableMakerTokenAmount = makerAmount.plus(makerFeeAmount);
+            transferrableMakerFeeTokenAmount = transferrableMakerTokenAmount;
+            remainingMakerTokenAmount = signedOrder.makerTokenAmount;
+            calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                           transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount, remainingMakerTokenAmount);
+            expect(calculator.computeRemainingMakerFillable()).to.be.bignumber.equal(remainingMakerTokenAmount);
+        });
+        it('calculates the correct amount when partially filled and funds available', () => {
+            signedOrder = buildSignedOrder();
+            remainingMakerTokenAmount = ZeroEx.toBaseUnitAmount(new BigNumber(1), decimals);
+            calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                           transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount, remainingMakerTokenAmount);
+            expect(calculator.computeRemainingMakerFillable()).to.be.bignumber.equal(remainingMakerTokenAmount);
+        });
+        it('calculates the amount to be 0 when all fee funds are transferred', () => {
+            signedOrder = buildSignedOrder();
+            transferrableMakerTokenAmount = zero;
+            transferrableMakerFeeTokenAmount = zero;
+            remainingMakerTokenAmount = signedOrder.makerTokenAmount;
+            calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                           transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount, remainingMakerTokenAmount);
+            expect(calculator.computeRemainingMakerFillable()).to.be.bignumber.equal(zero);
+        });
+        it('calculates the correct amount when balance is less than remaining fillable', () => {
+            signedOrder = buildSignedOrder();
+            const partiallyFilledAmount = ZeroEx.toBaseUnitAmount(new BigNumber(2), decimals);
+            remainingMakerTokenAmount = signedOrder.makerTokenAmount.minus(partiallyFilledAmount);
+            transferrableMakerTokenAmount = remainingMakerTokenAmount.minus(partiallyFilledAmount);
+            transferrableMakerFeeTokenAmount = transferrableMakerTokenAmount;
+
+            const orderToFeeRatio = signedOrder.makerTokenAmount.dividedToIntegerBy(signedOrder.makerFee);
+            const expectedFillableAmount = new BigNumber(450980);
+            calculator = new RemainingFillableCalculator(signedOrder, isMakerTokenZRX,
+                           transferrableMakerTokenAmount, transferrableMakerFeeTokenAmount, remainingMakerTokenAmount);
+            const calculatedFillableAmount = calculator.computeRemainingMakerFillable();
+            const numberOfFillsInRatio = calculatedFillableAmount.dividedToIntegerBy(orderToFeeRatio);
+            const calculatedFillableAmountPlusFees = calculatedFillableAmount.plus(numberOfFillsInRatio);
+            expect(calculatedFillableAmountPlusFees).to.be.bignumber.lessThan(transferrableMakerTokenAmount);
+            expect(calculatedFillableAmountPlusFees).to.be.bignumber.lessThan(remainingMakerTokenAmount);
+            expect(calculatedFillableAmount).to.be.bignumber.equal(expectedFillableAmount);
+            expect(numberOfFillsInRatio.decimalPlaces()).to.be.equal(0);
+        });
+    });
+});
--- a/packages/0x.js/test/subscription_test.ts
+++ b/packages/0x.js/test/subscription_test.ts
@@ -1,42 +1,44 @@
-import 'mocha';
-import * as _ from 'lodash';
-import * as chai from 'chai';
-import * as Sinon from 'sinon';
-import {chaiSetup} from './utils/chai_setup';
-import * as Web3 from 'web3';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
 import BigNumber from 'bignumber.js';
-import promisify = require('es6-promisify');
-import {web3Factory} from './utils/web3_factory';
+import * as chai from 'chai';
+import * as _ from 'lodash';
+import 'mocha';
+import * as Sinon from 'sinon';
+import * as Web3 from 'web3';
+
 import {
-    ZeroEx,
-    ZeroExError,
-    Token,
    ApprovalContractEventArgs,
-    TokenEvents,
    DecodedLogEvent,
+    Token,
+    TokenEvents,
+    ZeroEx,
 } from '../src';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
-import {TokenUtils} from './utils/token_utils';
-import {DoneCallback, BlockParamLiteral} from '../src/types';
+import {DoneCallback} from '../src/types';
+
+import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
+import {reportCallbackErrors} from './utils/report_callback_errors';
+import {web3Factory} from './utils/web3_factory';

 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);

 describe('SubscriptionTest', () => {
    let web3: Web3;
    let zeroEx: ZeroEx;
    let userAddresses: string[];
    let tokens: Token[];
-    let tokenUtils: TokenUtils;
    let coinbase: string;
    let addressWithoutFunds: string;
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
    before(async () => {
        web3 = web3Factory.create();
-        zeroEx = new ZeroEx(web3.currentProvider);
+        zeroEx = new ZeroEx(web3.currentProvider, config);
        userAddresses = await zeroEx.getAvailableAddressesAsync();
        tokens = await zeroEx.tokenRegistry.getTokensAsync();
-        tokenUtils = new TokenUtils(tokens);
        coinbase = userAddresses[0];
        addressWithoutFunds = userAddresses[1];
    });
@@ -48,9 +50,7 @@ describe('SubscriptionTest', () => {
    });
    describe('#subscribe', () => {
        const indexFilterValues = {};
-        const shouldThrowOnInsufficientBalanceOrAllowance = true;
        let tokenAddress: string;
-        const transferAmount = new BigNumber(42);
        const allowanceAmount = new BigNumber(42);
        let stubs: Sinon.SinonStub[] = [];
        before(() => {
@@ -62,22 +62,44 @@ describe('SubscriptionTest', () => {
            _.each(stubs, s => s.restore());
            stubs = [];
        });
-        it('Should receive the Error when an error occurs', (done: DoneCallback) => {
+        it('Should receive the Error when an error occurs while fetching the block', (done: DoneCallback) => {
            (async () => {
-                const callback = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
-                    expect(err).to.not.be.null();
-                    expect(logEvent).to.be.undefined();
-                    done();
-                };
+                const errMsg = 'Error fetching block';
+                const callback = reportCallbackErrors(done)(
+                    (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                        expect(err.message).to.be.equal(errMsg);
+                        expect(logEvent).to.be.undefined();
+                        done();
+                    },
+                );
                stubs = [
                  Sinon.stub((zeroEx as any)._web3Wrapper, 'getBlockAsync')
-                   .throws('JSON RPC error'),
+                   .throws(new Error(errMsg)),
                ];
                zeroEx.token.subscribe(
                    tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
                await zeroEx.token.setAllowanceAsync(tokenAddress, coinbase, addressWithoutFunds, allowanceAmount);
            })().catch(done);
-         });
+        });
+        it('Should receive the Error when an error occurs while reconciling the new block', (done: DoneCallback) => {
+            (async () => {
+                const errMsg = 'Error fetching logs';
+                const callback = reportCallbackErrors(done)(
+                    (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
+                        expect(err.message).to.be.equal(errMsg);
+                        expect(logEvent).to.be.undefined();
+                        done();
+                    },
+                );
+                stubs = [
+                  Sinon.stub((zeroEx as any)._web3Wrapper, 'getLogsAsync')
+                   .throws(new Error(errMsg)),
+                ];
+                zeroEx.token.subscribe(
+                    tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
+                await zeroEx.token.setAllowanceAsync(tokenAddress, coinbase, addressWithoutFunds, allowanceAmount);
+            })().catch(done);
+        });
        it('Should allow unsubscribeAll to be called successfully after an error', (done: DoneCallback) => {
            (async () => {
                const callback = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => _.noop;
@@ -85,11 +107,11 @@ describe('SubscriptionTest', () => {
                    tokenAddress, TokenEvents.Approval, indexFilterValues, callback);
                stubs = [
                  Sinon.stub((zeroEx as any)._web3Wrapper, 'getBlockAsync')
-                   .throws('JSON RPC error'),
+                   .throws(new Error('JSON RPC error')),
                ];
                zeroEx.token.unsubscribeAll();
                done();
            })().catch(done);
-         });
+        });
    });
 });
--- a/packages/0x.js/test/token_registry_wrapper_test.ts
+++ b/packages/0x.js/test/token_registry_wrapper_test.ts
@@ -1,15 +1,18 @@
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
+import {schemas, SchemaValidator} from '@0xproject/json-schemas';
+import * as chai from 'chai';
 import * as _ from 'lodash';
 import 'mocha';
-import * as chai from 'chai';
-import {SchemaValidator, schemas} from '@0xproject/json-schemas';
+
+import {Token, ZeroEx} from '../src';
+
 import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
 import {web3Factory} from './utils/web3_factory';
-import {ZeroEx, Token} from '../src';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';

 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);

 const TOKEN_REGISTRY_SIZE_AFTER_MIGRATION = 7;

@@ -24,9 +27,12 @@ describe('TokenRegistryWrapper', () => {
    const registeredName = '0x Protocol Token';
    const unregisteredSymbol = 'MAL';
    const unregisteredName = 'Malicious Token';
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
    before(async () => {
        const web3 = web3Factory.create();
-        zeroEx = new ZeroEx(web3.currentProvider);
+        zeroEx = new ZeroEx(web3.currentProvider, config);
        tokens = await zeroEx.tokenRegistry.getTokensAsync();
        _.map(tokens, token => {
            tokenAddressBySymbol[token.symbol] = token.address;
--- a/packages/0x.js/test/token_transfer_proxy_wrapper_test.ts
+++ b/packages/0x.js/test/token_transfer_proxy_wrapper_test.ts
@@ -1,17 +1,22 @@
 import * as chai from 'chai';
-import {chaiSetup} from './utils/chai_setup';
-import {web3Factory} from './utils/web3_factory';
+
 import {ZeroEx} from '../src';
-import {TokenTransferProxyWrapper} from '../src/contract_wrappers/token_transfer_proxy_wrapper';
+
+import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
+import {web3Factory} from './utils/web3_factory';

 chaiSetup.configure();
 const expect = chai.expect;

 describe('TokenTransferProxyWrapper', () => {
    let zeroEx: ZeroEx;
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
    before(async () => {
        const web3 = web3Factory.create();
-        zeroEx = new ZeroEx(web3.currentProvider);
+        zeroEx = new ZeroEx(web3.currentProvider, config);
    });
    describe('#isAuthorizedAsync', () => {
        it('should return false if the address is not authorized', async () => {
--- a/packages/0x.js/test/token_wrapper_test.ts
+++ b/packages/0x.js/test/token_wrapper_test.ts
@@ -1,31 +1,31 @@
-import 'mocha';
-import * as chai from 'chai';
-import {chaiSetup} from './utils/chai_setup';
-import * as Web3 from 'web3';
+import {BlockchainLifecycle} from '@0xproject/dev-utils';
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
 import BigNumber from 'bignumber.js';
-import promisify = require('es6-promisify');
-import {web3Factory} from './utils/web3_factory';
+import * as chai from 'chai';
+import 'mocha';
+import * as Web3 from 'web3';
+
 import {
+    ApprovalContractEventArgs,
+    BlockParamLiteral,
+    BlockRange,
+    DecodedLogEvent,
+    Token,
+    TokenEvents,
+    TransferContractEventArgs,
    ZeroEx,
    ZeroExError,
-    Token,
-    SubscriptionOpts,
-    TokenEvents,
-    ContractEvent,
-    TransferContractEventArgs,
-    ApprovalContractEventArgs,
-    TokenContractEventArgs,
-    LogWithDecodedArgs,
-    LogEvent,
-    DecodedLogEvent,
 } from '../src';
-import {BlockchainLifecycle} from './utils/blockchain_lifecycle';
+import {DoneCallback} from '../src/types';
+
+import {chaiSetup} from './utils/chai_setup';
+import {constants} from './utils/constants';
 import {TokenUtils} from './utils/token_utils';
-import {DoneCallback, BlockParamLiteral} from '../src/types';
+import {web3Factory} from './utils/web3_factory';

 chaiSetup.configure();
 const expect = chai.expect;
-const blockchainLifecycle = new BlockchainLifecycle();
+const blockchainLifecycle = new BlockchainLifecycle(constants.RPC_URL);

 describe('TokenWrapper', () => {
    let web3: Web3;
@@ -35,9 +35,14 @@ describe('TokenWrapper', () => {
    let tokenUtils: TokenUtils;
    let coinbase: string;
    let addressWithoutFunds: string;
+    let web3Wrapper: Web3Wrapper;
+    const config = {
+        networkId: constants.TESTRPC_NETWORK_ID,
+    };
    before(async () => {
        web3 = web3Factory.create();
-        zeroEx = new ZeroEx(web3.currentProvider);
+        zeroEx = new ZeroEx(web3.currentProvider, config);
+        web3Wrapper = new Web3Wrapper(web3.currentProvider);
        userAddresses = await zeroEx.getAvailableAddressesAsync();
        tokens = await zeroEx.tokenRegistry.getTokensAsync();
        tokenUtils = new TokenUtils(tokens);
@@ -62,8 +67,7 @@ describe('TokenWrapper', () => {
            const toAddress = addressWithoutFunds;
            const preBalance = await zeroEx.token.getBalanceAsync(token.address, toAddress);
            expect(preBalance).to.be.bignumber.equal(0);
-            const txHash = await zeroEx.token.transferAsync(token.address, fromAddress, toAddress, transferAmount);
-            const receipt = await zeroEx.awaitTransactionMinedAsync(txHash);
+            await zeroEx.token.transferAsync(token.address, fromAddress, toAddress, transferAmount);
            const postBalance = await zeroEx.token.getBalanceAsync(token.address, toAddress);
            return expect(postBalance).to.be.bignumber.equal(transferAmount);
        });
@@ -80,7 +84,7 @@ describe('TokenWrapper', () => {
            const toAddress = coinbase;
            return expect(zeroEx.token.transferAsync(
                nonExistentTokenAddress, fromAddress, toAddress, transferAmount,
-            )).to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+            )).to.be.rejectedWith(ZeroExError.TokenContractDoesNotExist);
        });
    });
    describe('#transferFromAsync', () => {
@@ -153,7 +157,7 @@ describe('TokenWrapper', () => {
            const nonExistentTokenAddress = '0x9dd402f14d67e001d8efbe6583e51bf9706aa065';
            return expect(zeroEx.token.transferFromAsync(
                nonExistentTokenAddress, fromAddress, toAddress, senderAddress, new BigNumber(42),
-            )).to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+            )).to.be.rejectedWith(ZeroExError.TokenContractDoesNotExist);
        });
    });
    describe('#getBalanceAsync', () => {
@@ -169,7 +173,7 @@ describe('TokenWrapper', () => {
                const nonExistentTokenAddress = '0x9dd402f14d67e001d8efbe6583e51bf9706aa065';
                const ownerAddress = coinbase;
                return expect(zeroEx.token.getBalanceAsync(nonExistentTokenAddress, ownerAddress))
-                    .to.be.rejectedWith(ZeroExError.ContractDoesNotExist);
+                    .to.be.rejectedWith(ZeroExError.TokenContractDoesNotExist);
            });
            it('should return a balance of 0 for a non-existent owner address', async () => {
                const token = tokens[0];
@@ -184,7 +188,7 @@ describe('TokenWrapper', () => {
            before(async () => {
                const hasAddresses = false;
                const web3WithoutAccounts = web3Factory.create(hasAddresses);
-                zeroExWithoutAccounts = new ZeroEx(web3WithoutAccounts.currentProvider);
+                zeroExWithoutAccounts = new ZeroEx(web3WithoutAccounts.currentProvider, config);
            });
            it('should return balance even when called with Web3 provider instance without addresses', async () => {
                    const token = tokens[0];
@@ -231,8 +235,10 @@ describe('TokenWrapper', () => {
            await zeroEx.token.setAllowanceAsync(zrx.address, coinbase, userWithNormalAllowance, transferAmount);
            await zeroEx.token.setUnlimitedAllowanceAsync(zrx.address, coinbase, userWithUnlimitedAllowance);

-            const initBalanceWithNormalAllowance = await promisify(web3.eth.getBalance)(userWithNormalAllowance);
-            const initBalanceWithUnlimitedAllowance = await promisify(web3.eth.getBalance)(userWithUnlimitedAllowance);
+            const initBalanceWithNormalAllowance = await web3Wrapper.getBalanceInWeiAsync(userWithNormalAllowance);
+            const initBalanceWithUnlimitedAllowance = await web3Wrapper.getBalanceInWeiAsync(
+                userWithUnlimitedAllowance,
+            );

            await zeroEx.token.transferFromAsync(
                zrx.address, coinbase, userWithNormalAllowance, userWithNormalAllowance, transferAmount,
@@ -241,8 +247,10 @@ describe('TokenWrapper', () => {
                zrx.address, coinbase, userWithUnlimitedAllowance, userWithUnlimitedAllowance, transferAmount,
            );

-            const finalBalanceWithNormalAllowance = await promisify(web3.eth.getBalance)(userWithNormalAllowance);
-            const finalBalanceWithUnlimitedAllowance = await promisify(web3.eth.getBalance)(userWithUnlimitedAllowance);
+            const finalBalanceWithNormalAllowance = await web3Wrapper.getBalanceInWeiAsync(userWithNormalAllowance);
+            const finalBalanceWithUnlimitedAllowance = await web3Wrapper.getBalanceInWeiAsync(
+                userWithUnlimitedAllowance,
+            );

            const normalGasCost = initBalanceWithNormalAllowance.minus(finalBalanceWithNormalAllowance);
            const unlimitedGasCost = initBalanceWithUnlimitedAllowance.minus(finalBalanceWithUnlimitedAllowance);
@@ -281,7 +289,7 @@ describe('TokenWrapper', () => {
            before(async () => {
                const hasAddresses = false;
                const web3WithoutAccounts = web3Factory.create(hasAddresses);
-                zeroExWithoutAccounts = new ZeroEx(web3WithoutAccounts.currentProvider);
+                zeroExWithoutAccounts = new ZeroEx(web3WithoutAccounts.currentProvider, config);
            });
            it('should get the proxy allowance', async () => {
                const token = tokens[0];
@@ -341,7 +349,6 @@ describe('TokenWrapper', () => {
    });
    describe('#subscribe', () => {
        const indexFilterValues = {};
-        const shouldThrowOnInsufficientBalanceOrAllowance = true;
        let tokenAddress: string;
        const transferAmount = new BigNumber(42);
        const allowanceAmount = new BigNumber(42);
@@ -361,10 +368,11 @@ describe('TokenWrapper', () => {
            (async () => {
                const callback = (err: Error, logEvent: DecodedLogEvent<TransferContractEventArgs>) => {
                    expect(logEvent).to.not.be.undefined();
-                    expect(logEvent.logIndex).to.be.equal(0);
-                    expect(logEvent.transactionIndex).to.be.equal(0);
-                    expect(logEvent.blockNumber).to.be.a('number');
-                    const args = logEvent.args;
+                    expect(logEvent.isRemoved).to.be.false();
+                    expect(logEvent.log.logIndex).to.be.equal(0);
+                    expect(logEvent.log.transactionIndex).to.be.equal(0);
+                    expect(logEvent.log.blockNumber).to.be.a('number');
+                    const args = logEvent.log.args;
                    expect(args._from).to.be.equal(coinbase);
                    expect(args._to).to.be.equal(addressWithoutFunds);
                    expect(args._value).to.be.bignumber.equal(transferAmount);
@@ -379,7 +387,8 @@ describe('TokenWrapper', () => {
            (async () => {
                const callback = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
                    expect(logEvent).to.not.be.undefined();
-                    const args = logEvent.args;
+                    expect(logEvent.isRemoved).to.be.false();
+                    const args = logEvent.log.args;
                    expect(args._owner).to.be.equal(coinbase);
                    expect(args._spender).to.be.equal(addressWithoutFunds);
                    expect(args._value).to.be.bignumber.equal(allowanceAmount);
@@ -390,7 +399,7 @@ describe('TokenWrapper', () => {
                await zeroEx.token.setAllowanceAsync(tokenAddress, coinbase, addressWithoutFunds, allowanceAmount);
            })().catch(done);
        });
-        it('Outstanding subscriptions are cancelled when zeroEx.setProviderAsync called', (done: DoneCallback) => {
+        it('Outstanding subscriptions are cancelled when zeroEx.setProvider called', (done: DoneCallback) => {
            (async () => {
                const callbackNeverToBeCalled = (err: Error, logEvent: DecodedLogEvent<ApprovalContractEventArgs>) => {
                    done(new Error('Expected this subscription to have been cancelled'));
@@ -402,7 +411,7 @@ describe('TokenWrapper', () => {
                    done();
                };
                const newProvider = web3Factory.getRpcProvider();
-                await zeroEx.setProviderAsync(newProvider);
+                zeroEx.setProvider(newProvider, constants.TESTRPC_NETWORK_ID);
                zeroEx.token.subscribe(
                    tokenAddress, TokenEvents.Transfer, indexFilterValues, callbackToBeCalled,
                );
@@ -425,15 +434,15 @@ describe('TokenWrapper', () => {
    describe('#getLogsAsync', () => {
        let tokenAddress: string;
        let tokenTransferProxyAddress: string;
-        const subscriptionOpts: SubscriptionOpts = {
-            fromBlock: BlockParamLiteral.Earliest,
+        const blockRange: BlockRange = {
+            fromBlock: 0,
            toBlock: BlockParamLiteral.Latest,
        };
        let txHash: string;
-        before(async () => {
+        before(() => {
            const token = tokens[0];
            tokenAddress = token.address;
-            tokenTransferProxyAddress = await zeroEx.proxy.getContractAddressAsync();
+            tokenTransferProxyAddress = zeroEx.proxy.getContractAddress();
        });
        it('should get logs with decoded args emitted by Approval', async () => {
            txHash = await zeroEx.token.setUnlimitedProxyAllowanceAsync(tokenAddress, coinbase);
@@ -441,7 +450,7 @@ describe('TokenWrapper', () => {
            const eventName = TokenEvents.Approval;
            const indexFilterValues = {};
            const logs = await zeroEx.token.getLogsAsync<ApprovalContractEventArgs>(
-                tokenAddress, eventName, subscriptionOpts, indexFilterValues,
+                tokenAddress, eventName, blockRange, indexFilterValues,
            );
            expect(logs).to.have.length(1);
            const args = logs[0].args;
@@ -456,7 +465,7 @@ describe('TokenWrapper', () => {
            const differentEventName = TokenEvents.Transfer;
            const indexFilterValues = {};
            const logs = await zeroEx.token.getLogsAsync(
-                tokenAddress, differentEventName, subscriptionOpts, indexFilterValues,
+                tokenAddress, differentEventName, blockRange, indexFilterValues,
            );
            expect(logs).to.have.length(0);
        });
@@ -470,7 +479,7 @@ describe('TokenWrapper', () => {
                _owner: coinbase,
            };
            const logs = await zeroEx.token.getLogsAsync<ApprovalContractEventArgs>(
-                tokenAddress, eventName, subscriptionOpts, indexFilterValues,
+                tokenAddress, eventName, blockRange, indexFilterValues,
            );
            expect(logs).to.have.length(1);
            const args = logs[0].args;
--- a/packages/0x.js/test/utils/chai_setup.ts
+++ b/packages/0x.js/test/utils/chai_setup.ts
@@ -1,7 +1,7 @@
 import * as chai from 'chai';
-import * as dirtyChai from 'dirty-chai';
-import ChaiBigNumber = require('chai-bignumber');
 import chaiAsPromised = require('chai-as-promised');
+import ChaiBigNumber = require('chai-bignumber');
+import * as dirtyChai from 'dirty-chai';

 export const chaiSetup = {
    configure() {
--- a/packages/0x.js/test/utils/constants.ts
+++ b/packages/0x.js/test/utils/constants.ts
@@ -1,8 +1,11 @@
 export const constants = {
    NULL_ADDRESS: '0x0000000000000000000000000000000000000000',
-    RPC_HOST: 'localhost',
-    RPC_PORT: 8545,
+    RPC_URL: 'http://localhost:8545/',
+    ROPSTEN_NETWORK_ID: 3,
+    KOVAN_NETWORK_ID: 42,
    TESTRPC_NETWORK_ID: 50,
-    KOVAN_RPC_URL: 'https://kovan.infura.io',
-    ROPSTEN_RPC_URL: 'https://ropsten.infura.io',
+    KOVAN_RPC_URL: 'https://kovan.infura.io/',
+    ROPSTEN_RPC_URL: 'https://ropsten.infura.io/',
+    ZRX_DECIMALS: 18,
+    GAS_ESTIMATE: 500000,
 };
--- a/packages/0x.js/test/utils/fill_scenarios.ts
+++ b/packages/0x.js/test/utils/fill_scenarios.ts
@@ -1,8 +1,15 @@
+import {Web3Wrapper} from '@0xproject/web3-wrapper';
 import BigNumber from 'bignumber.js';
-import {ZeroEx, Token, SignedOrder} from '../../src';
+
+import {SignedOrder, Token, ZeroEx} from '../../src';
+import {artifacts} from '../../src/artifacts';
+import {DummyTokenContract} from '../../src/contract_wrappers/generated/dummy_token';
 import {orderFactory} from '../utils/order_factory';
+
 import {constants} from './constants';

+const INITIAL_COINBASE_TOKEN_SUPPLY_IN_UNITS = new BigNumber(100);
+
 export class FillScenarios {
    private zeroEx: ZeroEx;
    private userAddresses: string[];
@@ -19,6 +26,23 @@ export class FillScenarios {
        this.zrxTokenAddress = zrxTokenAddress;
        this.exchangeContractAddress = exchangeContractAddress;
    }
+    public async initTokenBalancesAsync() {
+        const web3Wrapper = (this.zeroEx as any)._web3Wrapper as Web3Wrapper;
+        for (const token of this.tokens) {
+            if (token.symbol !== 'ZRX' && token.symbol !== 'WETH') {
+                const contractInstance = web3Wrapper.getContractInstance(
+                    artifacts.DummyTokenArtifact.abi, token.address,
+                );
+                const defaults = {};
+                const dummyToken = new DummyTokenContract(contractInstance, defaults);
+                const tokenSupply = ZeroEx.toBaseUnitAmount(INITIAL_COINBASE_TOKEN_SUPPLY_IN_UNITS, token.decimals);
+                const txHash = await dummyToken.setBalance.sendTransactionAsync(this.coinbase, tokenSupply, {
+                    from: this.coinbase,
+                });
+                await this.zeroEx.awaitTransactionMinedAsync(txHash);
+            }
+        }
+    }
    public async createFillableSignedOrderAsync(makerTokenAddress: string, takerTokenAddress: string,
                                                makerAddress: string, takerAddress: string,
                                                fillableAmount: BigNumber,
--- a/packages/0x.js/test/utils/order_factory.ts
+++ b/packages/0x.js/test/utils/order_factory.ts
@@ -1,6 +1,7 @@
-import * as _ from 'lodash';
 import BigNumber from 'bignumber.js';
-import {ZeroEx, SignedOrder} from '../../src';
+import * as _ from 'lodash';
+
+import {SignedOrder, ZeroEx} from '../../src';

 export const orderFactory = {
    async createSignedOrderAsync(
@@ -15,11 +16,11 @@ export const orderFactory = {
        takerTokenAddress: string,
        exchangeContractAddress: string,
        feeRecipient: string,
-        expirationUnixTimestampSec?: BigNumber): Promise<SignedOrder> {
+        expirationUnixTimestampSecIfExists?: BigNumber): Promise<SignedOrder> {
        const defaultExpirationUnixTimestampSec = new BigNumber(2524604400); // Close to infinite
-        expirationUnixTimestampSec = _.isUndefined(expirationUnixTimestampSec) ?
+        const expirationUnixTimestampSec = _.isUndefined(expirationUnixTimestampSecIfExists) ?
            defaultExpirationUnixTimestampSec :
-            expirationUnixTimestampSec;
+            expirationUnixTimestampSecIfExists;
        const order = {
            maker,
            taker,
--- a/packages/0x.js/test/utils/report_callback_errors.ts
+++ b/packages/0x.js/test/utils/report_callback_errors.ts
@@ -1,10 +1,10 @@
-import { DoneCallback } from '../../src/types';
+import {DoneCallback} from '../../src/types';

 export const reportCallbackErrors = (done: DoneCallback) => {
-    return (fAsync: (...args: any[]) => void|Promise<void>) => {
+    return (f: (...args: any[]) => void) => {
        const wrapped = async (...args: any[]) => {
            try {
-                await fAsync(...args);
+                f(...args);
            } catch (err) {
                done(err);
            }
--- a/packages/0x.js/test/utils/subproviders/empty_wallet_subprovider.ts
+++ b/packages/0x.js/test/utils/subproviders/empty_wallet_subprovider.ts
@@ -1,11 +1,13 @@
-import {JSONRPCPayload} from '../types';
+import {JSONRPCPayload} from '../../../src/types';

 /*
 * This class implements the web3-provider-engine subprovider interface and returns
 * that the provider has no addresses when queried.
 * Source: https://github.com/MetaMask/provider-engine/blob/master/subproviders/subprovider.js
 */
-export class EmptyWalletSubProvider {
+export class EmptyWalletSubprovider {
+    // This method needs to be here to satisfy the interface but linter wants it to be static.
+    // tslint:disable-next-line:prefer-function-over-method
    public handleRequest(payload: JSONRPCPayload, next: () => void, end: (err: Error|null, result: any) => void) {
        switch (payload.method) {
            case 'eth_accounts':
@@ -18,6 +20,7 @@ export class EmptyWalletSubProvider {
        }
    }
    // Required to implement this method despite not needing it for this subprovider
+    // tslint:disable-next-line:prefer-function-over-method
    public setEngine(engine: any) {
        // noop
    }
--- a/packages/0x.js/test/utils/subproviders/fake_gas_estimate_subprovider.ts
+++ b/packages/0x.js/test/utils/subproviders/fake_gas_estimate_subprovider.ts
@@ -0,0 +1,34 @@
+import {JSONRPCPayload} from '../../../src/types';
+
+/*
+ * This class implements the web3-provider-engine subprovider interface and returns
+ * the constant gas estimate when queried.
+ * HACK: We need this so that our tests don't use testrpc gas estimation which sometimes kills the node.
+ * Source: https://github.com/trufflesuite/ganache-cli/issues/417
+ * Source: https://github.com/trufflesuite/ganache-cli/issues/437
+ * Source: https://github.com/MetaMask/provider-engine/blob/master/subproviders/subprovider.js
+ */
+export class FakeGasEstimateSubprovider {
+    private constantGasAmount: number;
+    constructor(constantGasAmount: number) {
+        this.constantGasAmount = constantGasAmount;
+    }
+    // This method needs to be here to satisfy the interface but linter wants it to be static.
+    // tslint:disable-next-line:prefer-function-over-method
+    public handleRequest(payload: JSONRPCPayload, next: () => void, end: (err: Error|null, result: any) => void) {
+        switch (payload.method) {
+            case 'eth_estimateGas':
+                end(null, this.constantGasAmount);
+                return;
+
+            default:
+                next();
+                return;
+        }
+    }
+    // Required to implement this method despite not needing it for this subprovider
+    // tslint:disable-next-line:prefer-function-over-method
+    public setEngine(engine: any) {
+        // noop
+    }
+}
--- a/packages/0x.js/test/utils/token_utils.ts
+++ b/packages/0x.js/test/utils/token_utils.ts
@@ -1,7 +1,9 @@
 import * as _ from 'lodash';
-import {Token, InternalZeroExError} from '../../src/types';
+
+import {InternalZeroExError, Token} from '../../src/types';

 const PROTOCOL_TOKEN_SYMBOL = 'ZRX';
+const WETH_TOKEN_SYMBOL = 'WETH';

 export class TokenUtils {
    private tokens: Token[];
@@ -15,10 +17,17 @@ export class TokenUtils {
        }
        return zrxToken;
    }
-    public getNonProtocolTokens(): Token[] {
-        const nonProtocolTokens = _.filter(this.tokens, token => {
-            return token.symbol !== PROTOCOL_TOKEN_SYMBOL;
+    public getWethTokenOrThrow(): Token {
+        const wethToken = _.find(this.tokens, {symbol: WETH_TOKEN_SYMBOL});
+        if (_.isUndefined(wethToken)) {
+            throw new Error(InternalZeroExError.WethNotInTokenRegistry);
+        }
+        return wethToken;
+    }
+    public getDummyTokens(): Token[] {
+        const dummyTokens = _.filter(this.tokens, token => {
+            return !_.includes([PROTOCOL_TOKEN_SYMBOL, WETH_TOKEN_SYMBOL], token.symbol);
        });
-        return nonProtocolTokens;
+        return dummyTokens;
    }
 }
--- a/packages/0x.js/test/utils/web3_factory.ts
+++ b/packages/0x.js/test/utils/web3_factory.ts
@@ -5,9 +5,18 @@
 (global as any).XMLHttpRequest = undefined;
 import ProviderEngine = require('web3-provider-engine');
 import RpcSubprovider = require('web3-provider-engine/subproviders/rpc');
-import * as Web3 from 'web3';
+
+import {EmptyWalletSubprovider} from './subproviders/empty_wallet_subprovider';
+import {FakeGasEstimateSubprovider} from './subproviders/fake_gas_estimate_subprovider';
+
 import {constants} from './constants';
-import {EmptyWalletSubProvider} from '../../src/subproviders/empty_wallet_subprovider';
+
+// HACK: web3 leaks XMLHttpRequest into the global scope and causes requests to hang
+// because they are using the wrong XHR package.
+// importing web3 after subproviders fixes this issue
+// Filed issue: https://github.com/ethereum/web3.js/issues/844
+// tslint:disable-next-line:ordered-imports
+import * as Web3 from 'web3';

 export const web3Factory = {
    create(hasAddresses: boolean = true): Web3 {
@@ -18,12 +27,12 @@ export const web3Factory = {
    },
    getRpcProvider(hasAddresses: boolean = true): Web3.Provider {
        const provider = new ProviderEngine();
-        const rpcUrl = `http://${constants.RPC_HOST}:${constants.RPC_PORT}`;
        if (!hasAddresses) {
-            provider.addProvider(new EmptyWalletSubProvider());
+            provider.addProvider(new EmptyWalletSubprovider());
        }
+        provider.addProvider(new FakeGasEstimateSubprovider(constants.GAS_ESTIMATE));
        provider.addProvider(new RpcSubprovider({
-            rpcUrl,
+            rpcUrl: constants.RPC_URL,
        }));
        provider.start();
        return provider;
--- a/packages/0x.js/test/web3_wrapper_test.ts
+++ b/packages/0x.js/test/web3_wrapper_test.ts
@@ -1,29 +0,0 @@
-import * as chai from 'chai';
-import {web3Factory} from './utils/web3_factory';
-import {ZeroEx} from '../src/';
-import {Web3Wrapper} from '../src/web3_wrapper';
-import {constants} from './utils/constants';
-
-chai.config.includeStack = true;
-const expect = chai.expect;
-
-describe('Web3Wrapper', () => {
-    const web3Provider = web3Factory.create().currentProvider;
-    describe('#getNetworkIdIfExistsAsync', () => {
-        it('caches network id requests', async () => {
-            const web3Wrapper = (new ZeroEx(web3Provider) as any)._web3Wrapper as Web3Wrapper;
-            expect((web3Wrapper as any).networkIdIfExists).to.be.undefined();
-            const networkIdIfExists = await web3Wrapper.getNetworkIdIfExistsAsync();
-            expect((web3Wrapper as any).networkIdIfExists).to.be.equal(constants.TESTRPC_NETWORK_ID);
-        });
-        it('invalidates network id cache on setProvider call', async () => {
-            const web3Wrapper = (new ZeroEx(web3Provider) as any)._web3Wrapper as Web3Wrapper;
-            expect((web3Wrapper as any).networkIdIfExists).to.be.undefined();
-            const networkIdIfExists = await web3Wrapper.getNetworkIdIfExistsAsync();
-            expect((web3Wrapper as any).networkIdIfExists).to.be.equal(constants.TESTRPC_NETWORK_ID);
-            const newProvider = web3Factory.create().currentProvider;
-            web3Wrapper.setProvider(newProvider);
-            expect((web3Wrapper as any).networkIdIfExists).to.be.undefined();
-        });
-    });
-});
--- a/packages/abi-gen/CHANGELOG.md
+++ b/packages/abi-gen/CHANGELOG.md
@@ -0,0 +1,4 @@
+# CHANGELOG
+
+vx.x.x
+------------------------
--- a/packages/abi-gen/README.md
+++ b/packages/abi-gen/README.md
@@ -0,0 +1,39 @@
+# ABI Gen
+
+This package allows you to generate TypeScript contract wrappers from ABI files.
+It's heavily inspired by [Geth abigen](https://github.com/ethereum/go-ethereum/wiki/Native-DApps:-Go-bindings-to-Ethereum-contracts) but takes a different approach.
+You can write your custom handlebars templates which will allow you to seamlessly integrate the generated code into your existing codebase with existing conventions.
+
+For an example of the generated [wrapper files](https://github.com/0xProject/0x.js/tree/development/packages/0x.js/src/contract_wrappers/generated) check out 0x.js.
+[Here](https://github.com/0xProject/0x.js/tree/development/packages/0x.js/src/contract_templates) are the templates used to generate those files.
+
+## Instalation
+`yarn add -g @0xproject/abi-gen`
+## Usage
+```
+abi-gen
+Options:
+  --help           Show help                                           [boolean]
+  --version        Show version number                                 [boolean]
+  --abiGlob        Glob pattern to search for ABI JSON files [string] [required]
+  --templates      Folder where to search for templates      [string] [required]
+  --output         Folder where to put the output files      [string] [required]
+```
+## ABI files
+You're required to pass a [glob](https://en.wikipedia.org/wiki/Glob_(programming)) template where your abi files are located.
+TL;DR - here is the example from 0x.js.
+
+`--abiGlob 'src/artifacts/@(Exchange|Token|TokenTransferProxy|EtherToken|TokenRegistry).json`
+
+We could've just used `--abiGlob 'src/artifacts/*.json` but we wanted to exclude some of the abi files.
+
+The abi file should be either a [Truffle](http://truffleframework.com/) contract artifact (a JSON object with an abi key) or a JSON abi array.
+## How to write custom templates?
+The best way to get started is to copy [0x.js templates](https://github.com/0xProject/0x.js/tree/development/packages/0x.js/src/contract_templates) and start adjusting them for your needs.
+We use [handlebars](handlebarsjs.com) template engine under the hood.
+You need to have a master template called `contract.mustache`. it will be used to generate each contract wrapper. Although - you don't need and probably shouldn't write all your logic in a single template file. You can write [partial templates](http://handlebarsjs.com/partials.html) and as long as they are within a partials folder - they will be registered and available.
+## Which data/context do I get in my templates?
+For now you don't get much on top of methods abi, some useful helpers and a contract name because it was enough for our use-case, but if you need something else - create a PR.
+See the [type definition](https://github.com/0xProject/0x.js/tree/development/packages/abi-gen/src/types.ts) of what we pass to the render method.
+## Output files
+Output files will be generated within an output folder with names converted to camel case and taken from abi file names. If you already have some files in that folder they will be overwritten.
--- a/packages/abi-gen/package.json
+++ b/packages/abi-gen/package.json
@@ -0,0 +1,48 @@
+{
+  "name": "@0xproject/abi-gen",
+  "version": "0.0.2",
+  "description": "Generate contract wrappers from ABI and handlebars templates",
+  "main": "lib/index.js",
+  "types": "lib/index.d.ts",
+  "scripts": {
+    "lint": "tslint --project . 'src/**/*.ts'",
+    "clean": "shx rm -rf lib",
+    "build": "tsc"
+  },
+  "bin": {
+    "abi-gen": "lib/index.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/0xProject/0x.js.git"
+  },
+  "license": "Apache-2.0",
+  "bugs": {
+    "url": "https://github.com/0xProject/0x.js/issues"
+  },
+  "homepage": "https://github.com/0xProject/0x.js/packages/abi-gen/README.md",
+  "dependencies": {
+    "bignumber.js": "~4.1.0",
+    "chalk": "^2.3.0",
+    "glob": "^7.1.2",
+    "handlebars": "^4.0.11",
+    "lodash": "^4.17.4",
+    "mkdirp": "^0.5.1",
+    "to-snake-case": "^1.0.0",
+    "web3": "^0.20.0",
+    "yargs": "^10.0.3"
+  },
+  "devDependencies": {
+    "@0xproject/tslint-config": "^0.2.1",
+    "@types/glob": "^5.0.33",
+    "@types/handlebars": "^4.0.36",
+    "@types/mkdirp": "^0.5.1",
+    "@types/node": "^8.0.53",
+    "@types/yargs": "^10.0.0",
+    "npm-run-all": "^4.1.2",
+    "shx": "^0.2.2",
+    "tslint": "5.8.0",
+    "typescript": "~2.6.1",
+    "web3-typescript-typings": "^0.7.2"
+  }
+}
--- a/packages/abi-gen/scripts/postpublish.js
+++ b/packages/abi-gen/scripts/postpublish.js
@@ -0,0 +1,14 @@
+const postpublish_utils = require('../../../scripts/postpublish_utils');
+const packageJSON = require('../package.json');
+
+const subPackageName = packageJSON.name;
+
+postpublish_utils.getLatestTagAndVersionAsync(subPackageName)
+    .then(function(result) {
+        const releaseName = postpublish_utils.getReleaseName(subPackageName, result.version);
+        const assets = [];
+        return postpublish_utils.publishReleaseNotes(result.tag, releaseName, assets);
+    })
+    .catch (function(err) {
+        throw err;
+    });
--- a/packages/abi-gen/src/globals.d.ts
+++ b/packages/abi-gen/src/globals.d.ts
@@ -0,0 +1,4 @@
+declare function toSnakeCase(str: string): string;
+declare module 'to-snake-case' {
+    export = toSnakeCase;
+}
--- a/packages/abi-gen/src/index.ts
+++ b/packages/abi-gen/src/index.ts
@@ -0,0 +1,98 @@
+#!/usr/bin/env node
+
+import chalk from 'chalk';
+import * as fs from 'fs';
+import {sync as globSync} from 'glob';
+import * as Handlebars from 'handlebars';
+import * as _ from 'lodash';
+import * as mkdirp from 'mkdirp';
+import * as yargs from 'yargs';
+
+import toSnakeCase = require('to-snake-case');
+import * as Web3 from 'web3';
+
+import {ContextData, ParamKind} from './types';
+import {utils} from './utils';
+
+const ABI_TYPE_METHOD = 'function';
+const MAIN_TEMPLATE_NAME = 'contract.mustache';
+
+const args = yargs
+    .option('abiGlob', {
+        describe: 'Glob pattern to search for ABI JSON files',
+        type: 'string',
+        demand: true,
+    })
+    .option('templates', {
+        describe: 'Folder where to search for templates',
+        type: 'string',
+        demand: true,
+    })
+    .option('output', {
+        describe: 'Folder where to put the output files',
+        type: 'string',
+        demand: true,
+    })
+    .argv;
+
+function writeOutputFile(name: string, renderedTsCode: string): void {
+    const fileName = toSnakeCase(name);
+    const filePath = `${args.output}/${fileName}.ts`;
+    fs.writeFileSync(filePath, renderedTsCode);
+    utils.log(`Created: ${chalk.bold(filePath)}`);
+}
+
+Handlebars.registerHelper('parameterType', utils.solTypeToTsType.bind(utils, ParamKind.Input));
+Handlebars.registerHelper('returnType', utils.solTypeToTsType.bind(utils, ParamKind.Output));
+const partialTemplateFileNames = globSync(`${args.templates}/partials/**/*.mustache`);
+for (const partialTemplateFileName of partialTemplateFileNames) {
+    const namedContent = utils.getNamedContent(partialTemplateFileName);
+    Handlebars.registerPartial(namedContent.name, namedContent.content);
+}
+
+const mainTemplate = utils.getNamedContent(`${args.templates}/${MAIN_TEMPLATE_NAME}`);
+const template = Handlebars.compile<ContextData>(mainTemplate.content);
+const abiFileNames = globSync(args.abiGlob);
+if (_.isEmpty(abiFileNames)) {
+    utils.log(`${chalk.red(`No ABI files found.`)}`);
+    utils.log(`Please make sure you've passed the correct folder name and that the files have
+               ${chalk.bold('*.json')} extensions`);
+    process.exit(1);
+} else {
+    utils.log(`Found ${chalk.green(`${abiFileNames.length}`)} ${chalk.bold('ABI')} files`);
+    mkdirp.sync(args.output);
+}
+for (const abiFileName of abiFileNames) {
+    const namedContent = utils.getNamedContent(abiFileName);
+    utils.log(`Processing: ${chalk.bold(namedContent.name)}...`);
+    const parsedContent = JSON.parse(namedContent.content);
+    const ABI = _.isArray(parsedContent) ?
+                parsedContent : // ABI file
+                parsedContent.abi; // Truffle contracts file
+    if (_.isUndefined(ABI)) {
+        utils.log(`${chalk.red(`ABI not found in ${abiFileName}.`)}`);
+        utils.log(`Please make sure your ABI file is either an array with ABI entries or an object with the abi key`);
+        process.exit(1);
+    }
+    const methodAbis = ABI.filter((abi: Web3.AbiDefinition) => abi.type === ABI_TYPE_METHOD) as Web3.MethodAbi[];
+    const methodsData = _.map(methodAbis, methodAbi => {
+        _.map(methodAbi.inputs, input => {
+            if (_.isEmpty(input.name)) {
+                // Auto-generated getters don't have parameter names
+                input.name = 'index';
+            }
+        });
+        // This will make templates simpler
+        const methodData = {
+            ...methodAbi,
+            singleReturnValue: methodAbi.outputs.length === 1,
+        };
+        return methodData;
+    });
+    const contextData = {
+        contractName: namedContent.name,
+        methods: methodsData,
+    };
+    const renderedTsCode = template(contextData);
+    writeOutputFile(namedContent.name, renderedTsCode);
+}
--- a/packages/abi-gen/src/types.ts
+++ b/packages/abi-gen/src/types.ts
@@ -0,0 +1,15 @@
+import * as Web3 from 'web3';
+
+export enum ParamKind {
+    Input = 'input',
+    Output = 'output',
+}
+
+export interface Method extends Web3.MethodAbi {
+    singleReturnValue: boolean;
+}
+
+export interface ContextData {
+    contractName: string;
+    methods: Method[];
+}
--- a/packages/abi-gen/src/utils.ts
+++ b/packages/abi-gen/src/utils.ts
@@ -0,0 +1,56 @@
+import * as fs from 'fs';
+import * as _ from 'lodash';
+import * as path from 'path';
+
+import {ParamKind} from './types';
+
+export const utils = {
+    solTypeToTsType(paramKind: ParamKind, solType: string): string {
+        const trailingArrayRegex = /\[\d*\]$/;
+        if (solType.match(trailingArrayRegex)) {
+            const arrayItemSolType = solType.replace(trailingArrayRegex, '');
+            const arrayItemTsType = utils.solTypeToTsType(paramKind, arrayItemSolType);
+            const arrayTsType = `${arrayItemTsType}[]`;
+            return arrayTsType;
+        } else {
+            const solTypeRegexToTsType = [
+                {regex: '^string$', tsType: 'string'},
+                {regex: '^address$', tsType: 'string'},
+                {regex: '^bool$', tsType: 'boolean'},
+                {regex: '^u?int\\d*$', tsType: 'BigNumber'},
+                {regex: '^bytes\\d*$', tsType: 'string'},
+            ];
+            if (paramKind === ParamKind.Input) {
+                // web3 allows to pass those an non-bignumbers and that's nice
+                // but it always returns stuff as BigNumbers
+                solTypeRegexToTsType.unshift({regex: '^u?int(8|16|32)?$', tsType: 'number|BigNumber'});
+            }
+            for (const regexAndTxType of solTypeRegexToTsType) {
+                const {regex, tsType} = regexAndTxType;
+                if (solType.match(regex)) {
+                    return tsType;
+                }
+            }
+            throw new Error(`Unknown Solidity type found: ${solType}`);
+        }
+    },
+    log(...args: any[]): void {
+        console.log(...args); // tslint:disable-line:no-console
+    },
+    getPartialNameFromFileName(filename: string): string {
+        const name = path.parse(filename).name;
+        return name;
+    },
+    getNamedContent(filename: string): {name: string; content: string} {
+        const name = utils.getPartialNameFromFileName(filename);
+        try {
+            const content = fs.readFileSync(filename).toString();
+            return {
+                name,
+                content,
+            };
+        } catch (err) {
+            throw new Error(`Failed to read ${filename}: ${err}`);
+        }
+    },
+};
--- a/packages/abi-gen/tsconfig.json
+++ b/packages/abi-gen/tsconfig.json
@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "target": "es5",
+    "lib": ["es2015", "dom"],
+    "outDir": "lib",
+    "sourceMap": true,
+    "declaration": true,
+    "noImplicitAny": true,
+    "strictNullChecks": true
+  },
+  "include": [
+    "./src/**/*",
+    "./test/**/*",
+    "../../node_modules/web3-typescript-typings/index.d.ts"
+  ]
+}
--- a/packages/abi-gen/tslint.json
+++ b/packages/abi-gen/tslint.json
@@ -0,0 +1,5 @@
+{
+  "extends": [
+    "@0xproject/tslint-config"
+  ]
+}
--- a/packages/assert/README.md
+++ b/packages/assert/README.md
@@ -1,10 +1,54 @@
-assert
+@0xproject/assert
 ------

 Standard type and schema assertions to be used across all 0x projects and packages

-## Install
+## Installation

 ```bash
-npm install @0xproject/assert --save
+yarn add @0xproject/assert
+```
+
+## Usage
+
+```typescript
+import {assert} from '@0xproject/assert';
+
+assert.isValidBaseUnitAmount('baseUnitAmount', baseUnitAmount);
+```
+
+## Contributing
+
+We strongly encourage that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
+
+Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
+
+### Install Dependencies
+
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
+```bash
+yarn config set workspaces-experimental true
+```
+
+Then install dependencies
+```bash
+yarn install
+```
+
+### Build
+
+```bash
+yarn build
+```
+
+### Lint
+
+```bash
+yarn lint
+```
+
+### Run Tests
+
+```bash
+yarn test
 ```
--- a/packages/assert/package.json
+++ b/packages/assert/package.json
@@ -1,13 +1,13 @@
 {
  "name": "@0xproject/assert",
-  "version": "0.0.5",
+  "version": "0.0.7",
  "description": "Provides a standard way of performing type and schema validation across 0x projects",
  "main": "lib/src/index.js",
  "types": "lib/src/index.d.ts",
  "scripts": {
    "build": "tsc",
    "clean": "shx rm -rf _bundles lib test_temp",
-    "lint": "tslint src/**/*.ts test/**/*.ts",
+    "lint": "tslint --project . 'src/**/*.ts' 'test/**/*.ts'",
    "run_mocha": "mocha lib/test/**/*_test.js",
    "prepublishOnly": "run-p build",
    "test": "run-s clean build run_mocha",
@@ -23,23 +23,23 @@
  },
  "homepage": "https://github.com/0xProject/0x.js/packages/assert/README.md",
  "devDependencies": {
-    "@0xproject/tslint-config": "^0.1.1",
-    "@types/lodash": "^4.14.78",
+    "@0xproject/tslint-config": "^0.2.1",
+    "@types/lodash": "^4.14.86",
    "@types/mocha": "^2.2.42",
    "@types/valid-url": "^1.0.2",
    "chai": "^4.0.1",
    "chai-typescript-typings": "^0.0.1",
    "dirty-chai": "^2.0.1",
    "mocha": "^4.0.1",
-    "npm-run-all": "^4.1.1",
+    "npm-run-all": "^4.1.2",
    "shx": "^0.2.2",
    "tslint": "5.8.0",
-    "typescript": "^2.4.2"
+    "typescript": "~2.6.1"
  },
  "dependencies": {
-    "@0xproject/json-schemas": "^0.6.8",
+    "@0xproject/json-schemas": "^0.6.10",
+    "@0xproject/utils": "^0.1.0",
    "bignumber.js": "~4.1.0",
-    "ethereum-address": "^0.0.4",
    "lodash": "^4.17.4",
    "valid-url": "^1.0.9"
  }
--- a/packages/assert/src/globals.d.ts
+++ b/packages/assert/src/globals.d.ts
@@ -1,5 +1 @@
 declare module 'dirty-chai';
-
-declare module 'ethereum-address' {
-    const isAddress: (arg: any) => boolean;
-}
--- a/packages/assert/src/index.ts
+++ b/packages/assert/src/index.ts
@@ -1,11 +1,11 @@
+import {
+    Schema,
+    SchemaValidator,
+} from '@0xproject/json-schemas';
+import {addressUtils} from '@0xproject/utils';
 import BigNumber from 'bignumber.js';
-import * as ethereum_address from 'ethereum-address';
 import * as _ from 'lodash';
 import * as validUrl from 'valid-url';
-import {
-    SchemaValidator,
-    Schema,
-} from '@0xproject/json-schemas';

 const HEX_REGEX = /^0x[0-9A-F]*$/i;

@@ -35,9 +35,9 @@ export const assert = {
            this.typeAssertionMessage(variableName, 'HexString', value));
    },
    isETHAddressHex(variableName: string, value: string): void {
-        this.assert(ethereum_address.isAddress(value), this.typeAssertionMessage(variableName, 'ETHAddressHex', value));
+        this.assert(addressUtils.isAddress(value), this.typeAssertionMessage(variableName, 'ETHAddressHex', value));
        this.assert(
-            ethereum_address.isAddress(value) && value.toLowerCase() === value,
+            addressUtils.isAddress(value) && value.toLowerCase() === value,
            `Checksummed addresses are not supported. Convert ${variableName} to lower case before passing`,
        );
    },
@@ -62,7 +62,7 @@ export const assert = {
        this.assert(_.isBoolean(value), this.typeAssertionMessage(variableName, 'boolean', value));
    },
    isWeb3Provider(variableName: string, value: any): void {
-        const isWeb3Provider = _.isFunction((value as any).send) || _.isFunction((value as any).sendAsync);
+        const isWeb3Provider = _.isFunction((value).send) || _.isFunction((value).sendAsync);
        this.assert(isWeb3Provider, this.typeAssertionMessage(variableName, 'Web3.Provider', value));
    },
    doesConformToSchema(variableName: string, value: any, schema: Schema): void {
--- a/packages/assert/test/assert_test.ts
+++ b/packages/assert/test/assert_test.ts
@@ -1,8 +1,9 @@
-import 'mocha';
-import * as dirtyChai from 'dirty-chai';
-import * as chai from 'chai';
-import {BigNumber} from 'bignumber.js';
 import {schemas} from '@0xproject/json-schemas';
+import {BigNumber} from 'bignumber.js';
+import * as chai from 'chai';
+import * as dirtyChai from 'dirty-chai';
+import 'mocha';
+
 import {assert} from '../src/index';

 chai.config.includeStack = true;
@@ -24,7 +25,7 @@ describe('Assertions', () => {
                'test',
                42,
                false,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
            ];
            invalidInputs.forEach(input => expect(assert.isBigNumber.bind(assert, variableName, input)).to.throw());
@@ -42,7 +43,7 @@ describe('Assertions', () => {
                'test',
                42,
                false,
-                { random: 'test' },
+                {random: 'test'},
            ];
            invalidInputs.forEach(input => expect(assert.isUndefined.bind(assert, input, variableName)).to.throw());
        });
@@ -59,7 +60,7 @@ describe('Assertions', () => {
            const invalidInputs = [
                42,
                false,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
            ];
@@ -78,7 +79,7 @@ describe('Assertions', () => {
            const invalidInputs = [
                42,
                false,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
            ];
@@ -97,7 +98,7 @@ describe('Assertions', () => {
            const invalidInputs = [
                42,
                false,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
                '0x61a3ed31B43c8780e905a260a35faYfEc527be7516aa11c0256729b5b351bc33',
@@ -120,7 +121,7 @@ describe('Assertions', () => {
            const invalidInputs = [
                42,
                false,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
                '0x6FFFd0ae3f7d88c9b4925323f54c6e4b2918c5fd',
@@ -149,7 +150,7 @@ describe('Assertions', () => {
            const invalidInputs = [
                42,
                false,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
            ];
@@ -183,7 +184,7 @@ describe('Assertions', () => {
        it('should not throw for valid input', () => {
            const validInputs = [
                42,
-                0.00,
+                0,
                21e+42,
            ];
            validInputs.forEach(input => expect(assert.isNumber.bind(assert, variableName, input)).to.not.throw());
@@ -191,7 +192,7 @@ describe('Assertions', () => {
        it('should throw for invalid input', () => {
            const invalidInputs = [
                false,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
            ];
@@ -209,7 +210,7 @@ describe('Assertions', () => {
        it('should throw for invalid input', () => {
            const invalidInputs = [
                42,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
            ];
@@ -219,8 +220,8 @@ describe('Assertions', () => {
    describe('#isWeb3Provider', () => {
        it('should not throw for valid input', () => {
            const validInputs = [
-                { send: () => 45 },
-                { sendAsync: () => 45 },
+                {send: () => 45},
+                {sendAsync: () => 45},
            ];
            validInputs.forEach(input =>
                expect(assert.isWeb3Provider.bind(assert, variableName, input)).to.not.throw(),
@@ -229,7 +230,7 @@ describe('Assertions', () => {
        it('should throw for invalid input', () => {
            const invalidInputs = [
                42,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
            ];
@@ -252,7 +253,7 @@ describe('Assertions', () => {
        it('should throw for invalid input', () => {
            const invalidInputs = [
                42,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
            ];
@@ -276,7 +277,7 @@ describe('Assertions', () => {
        it('should throw for invalid input', () => {
            const invalidInputs = [
                42,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
                'ws://www.api.example-relayer.net',
@@ -308,7 +309,7 @@ describe('Assertions', () => {
        it('should throw for invalid input', () => {
            const invalidInputs = [
                42,
-                { random: 'test' },
+                {random: 'test'},
                undefined,
                new BigNumber(45),
                'www.google.com',
--- a/packages/connect/CHANGELOG.md
+++ b/packages/connect/CHANGELOG.md
@@ -1,5 +1,16 @@
 # CHANGELOG

-v0.0.2 - _November 22, 2017_
+v0.3.0 - _December 8, 2017_
+------------------------
+    * Expose WebSocketOrderbookChannel and associated types to public interface (#251)
+    * Remove tokenA and tokenB fields from OrdersRequest (#256)
+
+v0.2.0 - _November 29, 2017_
+------------------------
+    * Add SignedOrder and TokenTradeInfo to the public interface
+    * Add ECSignature and Order to the public interface
+    * Remove dependency on 0x.js
+
+v0.1.0 - _November 22, 2017_
 ------------------------
    * Provide a HttpClient class for interacting with standard relayer api compliant HTTP urls
--- a/packages/connect/README.md
+++ b/packages/connect/README.md
@@ -1 +1,51 @@
+@0xproject/connect
+------
+
 This repository contains a Javascript library that makes it easy to interact with Relayers that conform to the [Standard Relayer API](https://github.com/0xProject/standard-relayer-api)
+
+## Installation
+
+```bash
+yarn add @0xproject/connect
+```
+
+## Usage
+
+* [Docs](https://0xproject.com/docs/connect)
+* [Tutorials](https://0xproject.com/wiki#connect)
+
+## Contributing
+
+We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
+
+Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
+
+### Install Dependencies
+
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
+```bash
+yarn config set workspaces-experimental true
+```
+
+Then install dependencies
+```bash
+yarn install
+```
+
+### Build
+
+```bash
+yarn build
+```
+
+### Lint
+
+```bash
+yarn lint
+```
+
+### Run Tests
+
+```bash
+yarn test
+```
--- a/packages/connect/package.json
+++ b/packages/connect/package.json
@@ -1,6 +1,6 @@
 {
  "name": "@0xproject/connect",
-  "version": "0.0.1",
+  "version": "0.3.0",
  "description": "A javascript library for interacting with the standard relayer api",
  "keywords": [
    "connect",
@@ -15,9 +15,9 @@
    "build": "tsc",
    "clean": "shx rm -rf _bundles lib test_temp",
    "docs:json": "typedoc --excludePrivate --excludeExternals --target ES5 --json $JSON_FILE_PATH $PROJECT_DIR",
-    "upload_docs_json": "aws s3 cp docs/index.json $S3_URL --profile 0xproject --grants read=uri=http://acs.amazonaws.com/groups/global/AllUsers --content-type aplication/json",
+    "upload_docs_json": "aws s3 cp generated_docs/index.json $S3_URL --profile 0xproject --grants read=uri=http://acs.amazonaws.com/groups/global/AllUsers --content-type application/json",
    "copy_test_fixtures": "copyfiles -u 2 './test/fixtures/**/*.json' ./lib/test/fixtures",
-    "lint": "tslint src/**/*.ts test/**/*.ts",
+    "lint": "tslint --project . 'src/**/*.ts' 'test/**/*.ts'",
    "run_mocha": "mocha lib/test/**/*_test.js",
    "test": "run-s clean build copy_test_fixtures run_mocha",
    "test:circleci": "yarn test"
@@ -36,9 +36,8 @@
  },
  "homepage": "https://github.com/0xProject/0x.js/packages/connect/README.md",
  "dependencies": {
-    "0x.js": "^0.26.0",
-    "@0xproject/assert": "^0.0.5",
-    "@0xproject/json-schemas": "^0.6.8",
+    "@0xproject/assert": "^0.0.7",
+    "@0xproject/json-schemas": "^0.6.10",
    "bignumber.js": "~4.1.0",
    "isomorphic-fetch": "^2.2.1",
    "lodash": "^4.17.4",
@@ -46,25 +45,25 @@
    "websocket": "^1.0.25"
  },
  "devDependencies": {
-    "@0xproject/tslint-config": "^0.1.1",
+    "@0xproject/tslint-config": "^0.2.1",
    "@types/fetch-mock": "^5.12.1",
-    "@types/lodash": "^4.14.77",
+    "@types/lodash": "^4.14.86",
    "@types/mocha": "^2.2.42",
    "@types/query-string": "^5.0.1",
    "@types/websocket": "^0.0.34",
    "chai": "^4.0.1",
    "chai-as-promised": "^7.1.0",
-    "chai-as-promised-typescript-typings": "0.0.3",
+    "chai-as-promised-typescript-typings": "^0.0.3",
    "chai-typescript-typings": "^0.0.1",
    "copyfiles": "^1.2.0",
    "dirty-chai": "^2.0.1",
    "fetch-mock": "^5.13.1",
-    "mocha": "^4.0.0",
-    "npm-run-all": "^4.0.2",
+    "mocha": "^4.0.1",
+    "npm-run-all": "^4.1.2",
    "shx": "^0.2.2",
    "tslint": "5.8.0",
    "typedoc": "~0.8.0",
    "typescript": "~2.6.1",
-    "web3-typescript-typings": "^0.7.1"
+    "web3-typescript-typings": "^0.7.2"
  }
 }
--- a/packages/connect/scripts/postpublish.js
+++ b/packages/connect/scripts/postpublish.js
@@ -17,8 +17,9 @@ postpublish_utils.getLatestTagAndVersionAsync(subPackageName)
    })
    .then(function(release) {
        console.log('POSTPUBLISH: Release successful, generating docs...');
+        const jsonFilePath = __dirname + '/../' + postpublish_utils.generatedDocsDirectoryName + '/index.json';
        return execAsync(
-            'JSON_FILE_PATH=' +  __dirname + '/../docs/index.json PROJECT_DIR=' + __dirname + '/.. yarn docs:json',
+            'JSON_FILE_PATH=' + jsonFilePath + ' PROJECT_DIR=' + __dirname + '/.. yarn docs:json',
            {
                cwd,
            }
--- a/packages/connect/src/http_client.ts
+++ b/packages/connect/src/http_client.ts
@@ -1,21 +1,24 @@
-import 'isomorphic-fetch';
-import * as _ from 'lodash';
-import {BigNumber} from 'bignumber.js';
-import * as queryString from 'query-string';
 import {assert} from '@0xproject/assert';
 import {schemas} from '@0xproject/json-schemas';
-import {SignedOrder} from '0x.js';
+import {BigNumber} from 'bignumber.js';
+import 'isomorphic-fetch';
+import * as _ from 'lodash';
+import * as queryString from 'query-string';
+
+import {schemas as clientSchemas} from './schemas/schemas';
 import {
    Client,
    FeesRequest,
    FeesResponse,
+    HttpRequestOptions,
+    HttpRequestType,
    OrderbookRequest,
    OrderbookResponse,
    OrdersRequest,
+    SignedOrder,
    TokenPairsItem,
    TokenPairsRequest,
 } from './types';
-import {schemas as clientSchemas} from './schemas/schemas';
 import {typeConverters} from './utils/type_converters';

 // TODO: move this and bigNumberConfigs in the 0x.js package into one place
@@ -23,16 +26,6 @@ BigNumber.config({
    EXPONENTIAL_AT: 1000,
 });

-interface RequestOptions {
-    params?: object;
-    payload?: object;
-}
-
-enum RequestType {
-    Get = 'GET',
-    Post = 'POST',
-}
-
 /**
 * This class includes all the functionality related to interacting with a set of HTTP endpoints
 * that implement the standard relayer API v0
@@ -41,7 +34,7 @@ export class HttpClient implements Client {
    private apiEndpointUrl: string;
    /**
     * Instantiates a new HttpClient instance
-     * @param   url    The base url for making API calls
+     * @param   url    The relayer API base HTTP url you would like to interact with
     * @return  An instance of HttpClient
     */
    constructor(url: string) {
@@ -61,7 +54,7 @@ export class HttpClient implements Client {
        const requestOpts = {
            params: request,
        };
-        const tokenPairs = await this._requestAsync('/token_pairs', RequestType.Get, requestOpts);
+        const tokenPairs = await this._requestAsync('/token_pairs', HttpRequestType.Get, requestOpts);
        assert.doesConformToSchema(
            'tokenPairs', tokenPairs, schemas.relayerApiTokenPairsResponseSchema);
        _.each(tokenPairs, (tokenPair: object) => {
@@ -86,7 +79,7 @@ export class HttpClient implements Client {
        const requestOpts = {
            params: request,
        };
-        const orders = await this._requestAsync(`/orders`, RequestType.Get, requestOpts);
+        const orders = await this._requestAsync(`/orders`, HttpRequestType.Get, requestOpts);
        assert.doesConformToSchema('orders', orders, schemas.signedOrdersSchema);
        _.each(orders, (order: object) => typeConverters.convertOrderStringFieldsToBigNumber(order));
        return orders;
@@ -98,7 +91,7 @@ export class HttpClient implements Client {
     */
    public async getOrderAsync(orderHash: string): Promise<SignedOrder> {
        assert.doesConformToSchema('orderHash', orderHash, schemas.orderHashSchema);
-        const order = await this._requestAsync(`/order/${orderHash}`, RequestType.Get);
+        const order = await this._requestAsync(`/order/${orderHash}`, HttpRequestType.Get);
        assert.doesConformToSchema('order', order, schemas.signedOrderSchema);
        typeConverters.convertOrderStringFieldsToBigNumber(order);
        return order;
@@ -113,7 +106,7 @@ export class HttpClient implements Client {
        const requestOpts = {
            params: request,
        };
-        const orderBook = await this._requestAsync('/orderbook', RequestType.Get, requestOpts);
+        const orderBook = await this._requestAsync('/orderbook', HttpRequestType.Get, requestOpts);
        assert.doesConformToSchema('orderBook', orderBook, schemas.relayerApiOrderBookResponseSchema);
        typeConverters.convertOrderbookStringFieldsToBigNumber(orderBook);
        return orderBook;
@@ -134,7 +127,7 @@ export class HttpClient implements Client {
        const requestOpts = {
            payload: request,
        };
-        const fees = await this._requestAsync('/fees', RequestType.Post, requestOpts);
+        const fees = await this._requestAsync('/fees', HttpRequestType.Post, requestOpts);
        assert.doesConformToSchema('fees', fees, schemas.relayerApiFeesResponseSchema);
        typeConverters.convertStringsFieldsToBigNumbers(fees, ['makerFee', 'takerFee']);
        return fees;
@@ -148,9 +141,10 @@ export class HttpClient implements Client {
        const requestOpts = {
            payload: signedOrder,
        };
-        await this._requestAsync('/order', RequestType.Post, requestOpts);
+        await this._requestAsync('/order', HttpRequestType.Post, requestOpts);
    }
-    private async _requestAsync(path: string, requestType: RequestType, requestOptions?: RequestOptions): Promise<any> {
+    private async _requestAsync(path: string, requestType: HttpRequestType,
+                                requestOptions?: HttpRequestOptions): Promise<any> {
        const params = _.get(requestOptions, 'params');
        const payload = _.get(requestOptions, 'payload');
        let query = '';
--- a/packages/connect/src/index.ts
+++ b/packages/connect/src/index.ts
@@ -1,11 +1,19 @@
 export {HttpClient} from './http_client';
+export {WebSocketOrderbookChannel} from './ws_orderbook_channel';
 export {
    Client,
+    ECSignature,
    FeesRequest,
    FeesResponse,
+    Order,
+    OrderbookChannel,
+    OrderbookChannelHandler,
+    OrderbookChannelSubscriptionOpts,
    OrderbookRequest,
    OrderbookResponse,
    OrdersRequest,
+    SignedOrder,
    TokenPairsItem,
    TokenPairsRequest,
+    TokenTradeInfo,
 } from './types';
--- a/packages/connect/src/types.ts
+++ b/packages/connect/src/types.ts
@@ -1,6 +1,34 @@
-import {SignedOrder} from '0x.js';
 import {BigNumber} from 'bignumber.js';

+// TODO: Consolidate Order, SignedOrder and ECSignature into a shared package instead of duplicating them from 0x.js
+export interface Order {
+    maker: string;
+    taker: string;
+    makerFee: BigNumber;
+    takerFee: BigNumber;
+    makerTokenAmount: BigNumber;
+    takerTokenAmount: BigNumber;
+    makerTokenAddress: string;
+    takerTokenAddress: string;
+    salt: BigNumber;
+    exchangeContractAddress: string;
+    feeRecipient: string;
+    expirationUnixTimestampSec: BigNumber;
+}
+
+export interface SignedOrder extends Order {
+    ecSignature: ECSignature;
+}
+
+/**
+ * Elliptic Curve signature
+ */
+export interface ECSignature {
+    v: number;
+    r: string;
+    s: string;
+}
+
 export interface Client {
    getTokenPairsAsync: (request?: TokenPairsRequest) => Promise<TokenPairsItem[]>;
    getOrdersAsync: (request?: OrdersRequest) => Promise<SignedOrder[]>;
@@ -15,11 +43,27 @@ export interface OrderbookChannel {
    close: () => void;
 }

+/*
+ * baseTokenAddress: The address of token designated as the baseToken in the currency pair calculation of price
+ * quoteTokenAddress: The address of token designated as the quoteToken in the currency pair calculation of price
+ * snapshot: If true, a snapshot of the orderbook will be sent before the updates to the orderbook
+ * limit: Maximum number of bids and asks in orderbook snapshot
+ */
+export interface OrderbookChannelSubscriptionOpts {
+    baseTokenAddress: string;
+    quoteTokenAddress: string;
+    snapshot: boolean;
+    limit: number;
+}
+
 export interface OrderbookChannelHandler {
-    onSnapshot: (channel: OrderbookChannel, snapshot: OrderbookResponse) => void;
-    onUpdate: (channel: OrderbookChannel, order: SignedOrder) => void;
-    onError: (channel: OrderbookChannel, err: Error) => void;
-    onClose: (channel: OrderbookChannel) => void;
+    onSnapshot: (channel: OrderbookChannel, subscriptionOpts: OrderbookChannelSubscriptionOpts,
+                 snapshot: OrderbookResponse) => void;
+    onUpdate: (channel: OrderbookChannel, subscriptionOpts: OrderbookChannelSubscriptionOpts,
+               order: SignedOrder) => void;
+    onError: (channel: OrderbookChannel, subscriptionOpts: OrderbookChannelSubscriptionOpts,
+              err: Error) => void;
+    onClose: (channel: OrderbookChannel, subscriptionOpts: OrderbookChannelSubscriptionOpts) => void;
 }

 export type OrderbookChannelMessage =
@@ -35,30 +79,31 @@ export enum OrderbookChannelMessageTypes {

 export interface SnapshotOrderbookChannelMessage {
    type: OrderbookChannelMessageTypes.Snapshot;
+    requestId: number;
    payload: OrderbookResponse;
 }

 export interface UpdateOrderbookChannelMessage {
    type: OrderbookChannelMessageTypes.Update;
+    requestId: number;
    payload: SignedOrder;
 }

 export interface UnknownOrderbookChannelMessage {
    type: OrderbookChannelMessageTypes.Unknown;
+    requestId: number;
    payload: undefined;
 }

-/*
- * baseTokenAddress: The address of token designated as the baseToken in the currency pair calculation of price
- * quoteTokenAddress: The address of token designated as the quoteToken in the currency pair calculation of price
- * snapshot: If true, a snapshot of the orderbook will be sent before the updates to the orderbook
- * limit: Maximum number of bids and asks in orderbook snapshot
- */
-export interface OrderbookChannelSubscriptionOpts {
-    baseTokenAddress: string;
-    quoteTokenAddress: string;
-    snapshot: boolean;
-    limit: number;
+export enum WebsocketConnectionEventType {
+    Close = 'close',
+    Error = 'error',
+    Message = 'message',
+}
+
+export enum WebsocketClientEventType {
+    Connect = 'connect',
+    ConnectFailed = 'connectFailed',
 }

 export interface TokenPairsRequest {
@@ -83,8 +128,6 @@ export interface OrdersRequest {
    tokenAddress?: string;
    makerTokenAddress?: string;
    takerTokenAddress?: string;
-    tokenA?: string;
-    tokenB?: string;
    maker?: string;
    taker?: string;
    trader?: string;
@@ -118,3 +161,13 @@ export interface FeesResponse {
    makerFee: BigNumber;
    takerFee: BigNumber;
 }
+
+export interface HttpRequestOptions {
+    params?: object;
+    payload?: object;
+}
+
+export enum HttpRequestType {
+    Get = 'GET',
+    Post = 'POST',
+}
--- a/packages/connect/src/utils/orderbook_channel_message_parsers.ts
+++ b/packages/connect/src/utils/orderbook_channel_message_parsers.ts
@@ -1,11 +1,12 @@
-import * as _ from 'lodash';
-import {SignedOrder} from '0x.js';
 import {assert} from '@0xproject/assert';
 import {schemas} from '@0xproject/json-schemas';
+import * as _ from 'lodash';
+
 import {
    OrderbookChannelMessage,
    OrderbookChannelMessageTypes,
 } from '../types';
+
 import {typeConverters} from './type_converters';

 export const orderbookChannelMessageParsers = {
@@ -13,28 +14,24 @@ export const orderbookChannelMessageParsers = {
        const messageObj = JSON.parse(utf8Data);
        const type: string = _.get(messageObj, 'type');
        assert.assert(!_.isUndefined(type), `Message is missing a type parameter: ${utf8Data}`);
+        assert.isString('type', type);
        switch (type) {
            case (OrderbookChannelMessageTypes.Snapshot): {
                assert.doesConformToSchema('message', messageObj, schemas.relayerApiOrderbookChannelSnapshotSchema);
                const orderbook = messageObj.payload;
                typeConverters.convertOrderbookStringFieldsToBigNumber(orderbook);
-                return {
-                    type,
-                    payload: orderbook,
-                };
+                return messageObj;
            }
            case (OrderbookChannelMessageTypes.Update): {
                assert.doesConformToSchema('message', messageObj, schemas.relayerApiOrderbookChannelUpdateSchema);
                const order = messageObj.payload;
                typeConverters.convertOrderStringFieldsToBigNumber(order);
-                return {
-                    type,
-                    payload: order,
-                };
+                return messageObj;
            }
            default: {
                return {
                    type: OrderbookChannelMessageTypes.Unknown,
+                    requestId: 0,
                    payload: undefined,
                };
            }
--- a/packages/connect/src/utils/type_converters.ts
+++ b/packages/connect/src/utils/type_converters.ts
@@ -1,5 +1,5 @@
-import * as _ from 'lodash';
 import {BigNumber} from 'bignumber.js';
+import * as _ from 'lodash';

 // TODO: convert all of these to non-mutating, pure functions
 export const typeConverters = {
--- a/Show More
+++ b/Show More