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Web3.js is a robust and flexible collection of TypeScript and JavaScript libraries that allows developers to interact with local or remote Ethereum nodes (or any EVM-compatible blockchain) over HTTP, IPC or WebSocket connections. It is a powerful and efficient toolkit for crafting applications within the Ethereum ecosystem and beyond.

This documentation is the entrypoint to Web3.js for developers. It covers basic and advanced usage with examples, and includes comprehensive API documentation as well as guides for common tasks, like upgrading from older versions.

Features of Web3.js v4


Web3.js is a modular collection of packages, each of which serves a specific needs. This means developers don't need to install the entire Web3 library for most use cases. Instead, necessary packages are selectively installed for a more efficient development experience. Here is an overview of a selection of available packages:

  • Web3Eth: The web3-eth package is the entrypoint to Web3.js - it's the control center for managing interactions with Ethereum and other EVM-compatible networks.

  • Net: The web3-net package provides discovery and interactions for an Ethereum node's network properties.

  • Accounts: The web3-eth-accounts package has tools for creating Ethereum accounts and the secure signing of transactions and data.

  • Personal: Use web3-eth-personal for direct communication about your accounts with the Ethereum node, which streamlines account management during development.

    NOTE: For enhanced security in production and when interacting with public nodes, consider using web3-eth-accounts for local signing operations, which keeps your private keys and sensitive information secure on your local machine

  • Utils: The web3-utils package provides helpers to perform a range of essential Ethereum development tasks, including converting data formats, checking addresses, encoding and decoding data, hashing, handling numbers, and much more..

  • Contract: The web3-eth-contract package makes it easy to interact with smart contracts through JavaScript or TypeScript, which streamlines the development process and makes it less error-prone.

  • ABI: The web3-eth-abi package simplifies decoding logs and parameters, encoding function calls and signatures, and inferring types for efficient Ethereum smart contract interactions.

  • ENS: The web3-eth-ens package makes it easy for developers to communicate with the Ethereum Name Service (ENS).

  • Iban: The web3-eth-iban package allows you to switch between Ethereum addresses and special banking-like addresses (IBAN or BBAN) and simplifies conversion between the types.

Additional supporting packages

  • Web3 Core: subscriptions, request management, and configuration used by other Web3 packages

  • Web3 Types: data structures, objects, interfaces and types used by Web3

  • Web3 Validator: runtime type validation against predefined types or custom schemas

  • Web3 Errors: error codes and common error classes that are used by other Web3 packages

  • Web3 RPC Methods: functions for making RPC requests to Ethereum using a given provider

Advantages over other libraries

  • Extensive Documentation and Community: Web3.js is one of the most established Ethereum libraries, which means it benefits from extensive documentation and a large, active community. Web3.js is widely adopted and has been thoroughly tested in various production environments, and is compatible with a broad range of other tools and services in the Ethereum ecosystem.

  • Modular Design: Web3.js is designed to be modular, which allows developers to use specific packages according to their needs. This leads to smaller bundle sizes and faster load times for web applications.

  • Active Development and Support: Web3.js sees regular updates and active development. This support is crucial for developers needing assurance that the library they're using will keep pace with the evolving Ethereum landscape.