Web3.js

Web3.js is one of the oldest and most established JavaScript libraries for interacting with Ethereum and other EVM-compatible blockchains. Launched in 2014, it provides a modular, TypeScript-friendly API that abstracts the Ethereum JSON-RPC interface, enabling developers to deploy and interact with smart contracts, subscribe to blockchain events, and manage accounts and transactions. Web3.js supports both ECMAScript modules and CommonJS, making it flexible for various JavaScript project setups.

The library offers dynamic contract typing, strict TypeScript enforcement for safer code, and efficient ABI encoding and decoding. It also includes utilities for interacting with Ethereum Name Service (ENS), querying blockchain state, and signing data or transactions. Web3.js is designed to align closely with official Ethereum terminology, improving developer clarity and reducing errors. Integration typically involves installing the package via npm or yarn, then creating a Web3 instance with a provider such as MetaMask or a remote node endpoint.

Despite its long history and broad adoption, Web3.js is scheduled for sunset on March 4th, 2025, with migration guides available for transitioning to newer alternatives. However, it remains widely used in production, with notable integrations including DeFi Saver and Chainstack. Its extensive documentation, active community, and plugin ecosystem continue to support developers building decentralized applications. Getting started involves importing the library, setting a provider, and using the contract and event APIs to interact with smart contracts and blockchain data.