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Ethereum JavaScript API
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web3.js - Ethereum JavaScript API

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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


meteor npm install --save web3@1.x


import Web3 from 'web3';

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

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

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

There you go, now you can use it:


Usage with TypeScript

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 for example a node app you just have to enable esModuleInterop in your tsconfig compile option, also enable allowSyntheticDefaultImports for typesystem compatibility:

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


Documentation can be found at read the docs


  • All contributions have to go into the 1.0 branch
  • Please follow the code style of the other files, we use 4 spaces as tabs.



npm install # install all dependencies for npm run bootstrap
npm run bootstrap # install all dependencies and symlinks the internal modules for all modules
npm run build # runs rollup
npm run test # runs all tests 
npm run clean # removes all the node_modules folders in all modules


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