web3

What is web3?

The web3 npm package is a collection of libraries that allow you to interact with a local or remote Ethereum node, using HTTP, IPC, or WebSocket. It provides functionalities for interacting with smart contracts, sending transactions, and querying blockchain data.

What are web3's main functionalities?

Connecting to an Ethereum Node

This feature allows you to connect to an Ethereum node using an HTTP provider. You can replace the URL with your own node's URL or use a service like Infura.

const Web3 = require('web3');
const web3 = new Web3('https://mainnet.infura.io/v3/YOUR_INFURA_PROJECT_ID');

Interacting with Smart Contracts

This feature allows you to interact with smart contracts deployed on the Ethereum blockchain. You need the contract's ABI and address to create a contract instance and call its methods.

const contractABI = [/* ABI array */];
const contractAddress = '0xYourContractAddress';
const contract = new web3.eth.Contract(contractABI, contractAddress);
contract.methods.yourMethod().call().then(console.log);

Sending Transactions

This feature allows you to send transactions on the Ethereum network. You need the sender's account address and private key to sign and send the transaction.

const account = '0xYourAccountAddress';
const privateKey = 'your_private_key';
const tx = {
  to: '0xRecipientAddress',
  value: web3.utils.toWei('0.1', 'ether'),
  gas: 2000000
};
web3.eth.accounts.signTransaction(tx, privateKey).then(signed => {
  web3.eth.sendSignedTransaction(signed.rawTransaction)
    .on('receipt', console.log);
});

Querying Blockchain Data

This feature allows you to query data from the blockchain, such as retrieving the latest block information.

web3.eth.getBlock('latest').then(console.log);

Other packages similar to web3

ethers

The ethers.js library aims to be a complete and compact library for interacting with the Ethereum Blockchain and its ecosystem. It provides similar functionalities to web3, such as connecting to Ethereum nodes, interacting with smart contracts, and sending transactions. Ethers.js is known for its smaller size and better documentation.

truffle

Truffle is a development environment, testing framework, and asset pipeline for Ethereum. While it provides some overlapping functionalities with web3, such as interacting with smart contracts, it is more focused on the development and deployment of smart contracts.

embark

Embark is a framework for serverless Decentralized Applications using Ethereum, IPFS, and other platforms. It provides functionalities for smart contract management, decentralized storage, and communication, making it a more comprehensive solution compared to web3.

README

web3

This is the main package of web3.js.

Please read the main README and documentation for more.

Installation

Node.js

npm install web3

Types

All the TypeScript typings are placed in the types folder.

Changelog

[1.3.5]

Added

• GitHub action for running tests for web3-eth2-core and web3-eth2-beaconchain packages (#3892)
• Added description to documentation on how to connect using a remote node provider (#3884)
• Added Security risk warning to docs for web3.utils.soliditySha3 (#3908)
• .nvmrc file using Node.js version v.14.15.1 (#3817)
• Add commitment to semantic versioning since version 1.3.0 and onwards (#3961)

Changed

• Unified babel compiler for web3-eth2-core and web3-eth2-beaconchain (#3892)
• Renamed the tsc script in all packages to compile; updates the corresponding lerna run usage in the main package.json (#3894)
• moved deprecation warnings to postinstall scripts (#3917)
• Upgrade @chainsafe/geth-dev-assistant from 0.1.5 to 0.1.9 (#3950)
• Replaced hardcoded infura link with GitHub Secret for some tests (#3943)
• Bump elliptic from 6.5.3 to 6.5.4 for web3-eth-accounts (#3941)
• Bump elliptic from 6.5.3 to 6.5.4 for web3-bzz (#3940)
• Bump elliptic from 6.5.3 to 6.5.4 for web3-core-requestmanager (#3945)
• Rewrite web3-eth-iban in ES6 (#3955)