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Ethereum JavaScript API

This is the Ethereum compatible JavaScript API which implements the Generic JSON RPC spec. It's available on npm as a node module, for Bower and component as embeddable scripts, and as a meteor.js package.

You need to run a local Ethereum node to use this library.

Documentation

Table of Contents

• Installation
  • Node.js
  • Yarn
  • Meteor.js
  • As a Browser module
• Usage
  • Migration from 0.13.0 to 0.14.0
• Contribute!
  • Requirements
  • Building (gulp)
  • Testing (mocha)
  • Community
  • Other implementations
• License

Installation

Node.js

npm install web3

Yarn

yarn add web3

Meteor.js

meteor add ethereum:web3

As a Browser module

CDN

<script src="https://cdn.jsdelivr.net/gh/ethereum/[email protected]/dist/web3.min.js" integrity="sha256-nWBTbvxhJgjslRyuAKJHK+XcZPlCnmIAAMixz6EefVk=" crossorigin="anonymous"></script>

Bower

bower install web3

Component

component install ethereum/web3.js

• Include web3.min.js in your html file. (not required for the meteor package)

Usage

Use the web3 object directly from the global namespace:

console.log(web3); // {eth: .., shh: ...} // It's here!

Set a provider (HttpProvider):

if (typeof web3 !== 'undefined') {
  web3 = new Web3(web3.currentProvider);
} else {
  // Set the provider you want from Web3.providers
  web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
}

Set a provider (HttpProvider using HTTP Basic Authentication):

web3.setProvider(new web3.providers.HttpProvider('http://' + BasicAuthUsername + ':' + BasicAuthPassword + '@localhost:8545'));

There you go, now you can use it:

var coinbase = web3.eth.coinbase;
var balance = web3.eth.getBalance(coinbase);

You can find more examples in the example directory.

Migration from 0.13.0 to 0.14.0

web3.js version 0.14.0 supports multiple instances of the web3 object. To migrate to this version, please follow the guide:

-var web3 = require('web3');
+var Web3 = require('web3');
+var web3 = new Web3();

Contribute!

Requirements

• Node.js
• npm

# On Linux:
sudo apt-get update
sudo apt-get install nodejs
sudo apt-get install npm
sudo apt-get install nodejs-legacy

Building (gulp)

npm run-script build

Testing (mocha)

npm test

Community

• Gitter
• Forum

Other implementations

• Python Web3.py
• Haskell hs-web3
• Java web3j
• Scala web3j-scala
• Purescript purescript-web3
• PHP web3.php
• PHP ethereum-php
• Rust rust-web3
• Swift web3swift

License

LGPL-3.0+ © 2015 Contributors