what-is-web3js.md

What Is Web3js

Category: Blockchain

web3.js is a JavaScript API for interacting with the Ethereum blockchain via local or remote nodes. Connectivity is over HTTP, IPC, or WebSocket.

Add web3.js to your project:

yarn add web3

Most calls to web3.js are asynchronous with responses being handled using a callback or async/await block.

For example:

// Get an array of addresses controlled by a node
const addresses = await web3.eth.getAccounts();

Because the Etheruem blockchain has different levels of finality, web3.js can return multiple stages of an action using a "PromiEvent". This allows smart contracts or functions, for example, the method web3.eth.sendTransaction, to subscribe to confirmations, errors, and the transaction hash.

See web3.js - Ethereum JavaScript API for more details.