This is the Ethereum JavaScript API which connects to the Generic JSON-RPC spec.

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

Please read the documentation for more.

npm install web3

yarn add web3

Use the prebuilt dist/web3.min.js, or build using the web3.js repository:

npm run build

Then include dist/web3.min.js in your html file. This will expose Web3 on the window object.

Or via jsDelivr CDN:

<script src="https://cdn.jsdelivr.net/npm/web3@latest/dist/web3.min.js"></script>

UNPKG:

<script src="https://unpkg.com/web3@latest/dist/web3.min.js"></script>

// In Node.js
const Web3 = require('web3');

let web3 = new Web3('ws://localhost:8546');
console.log(web3);
> {
    eth: ... ,
    shh: ... ,
    utils: ...,
    ...
}

Additionally you can set a provider using web3.setProvider() (e.g. WebsocketProvider):

web3.setProvider('ws://localhost:8546');
// or
web3.setProvider(new Web3.providers.WebsocketProvider('ws://localhost:8546'));

There you go, now you can use it:

web3.eth.getAccounts().then(console.log);

We support types within the repo itself. Please open an issue here if you find any wrong types.

You can use web3.js as follows:

import Web3 from 'web3';
const web3 = new Web3('ws://localhost:8546');

If you are using the types in a commonjs module, like in a Node app, you just have to enable esModuleInterop and allowSyntheticDefaultImports in your tsconfig for typesystem compatibility:

"compilerOptions": {
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    ....

If you are using Ionic/Angular at a version >5 you may run into a build error in which modules crypto and stream are undefined

a work around for this is to go into your node-modules and at /angular-cli-files/models/webpack-configs/browser.js change the node: false to node: {crypto: true, stream: true} as mentioned here

Another variation of this problem was an issue opned on angular-cli: angular/angular-cli#1548

Documentation can be found at ReadTheDocs.

• Node.js
• npm

sudo apt-get update
sudo apt-get install nodejs
sudo apt-get install npm

Build the web3.js package:

npm run build

npm test

Please follow the Contribution Guidelines and Review Guidelines.

This project adheres to the Release Guidelines.

• Gitter
• StackExchange

• Haskell: hs-web3
• Java: web3j
• PHP: web3.php
• Purescript: purescript-web3
• Python: Web3.py
• Ruby: ethereum.rb
• Scala: web3j-scala