Web3.js was created as a way for developers to easily connect their DApps with information on the Ethereum blockchain. Using its modular libraries, developers can interact with smart contracts as if they are TypeScript/JavaScript objects, subscribe to on-chain events, get block state directly from Ethereum nodes, and more. Its version 4 has been rewritten in TypeScript and provided new features like Plugins. The library has over 500,000 weekly downloads and is used by some of industry leading projects such as Truffle.