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.
web3.js
This is the main package of web3.js, it contains a collection of comprehensive TypeScript libraries for Interaction with the Ethereum JSON RPC API and utility functions.
Features
- Web3.js Plugins](https://docs.web3js.org/guides/web3_plugin_guide/): Enhance or add any functionality by creating scalable web3 plugins for any project.
- Abstractions over the JSON-RPC API: Simplifying interaction for your Developer Experience.
- Language aligned to the official [Ethereum terminology](https://ethereum.org/en/glossary
- Tree-shaking focus: Include only what you need during bundling for optimized performance.
- Dynamic contract types and full API in TypeScript: Enforced with strict types for enhanced security and safety.
- Complete utilities and functionalities for all your Ethereum needs
- More efficient ABI Encoder & Decoder
- Extensive documentation with guides and APIs
- Large collection of test cases
- First-class APIs for interacting with [Smart Contracts](https://ethereum.org/en/glossary#smart-contract
- ESM and CJS module builds: Support for both ECMAScript module and CommonJS module builds for flexible integration with various project setups.
- Contracts dynamic types](https://docs.web3js.org/guides/smart_contracts/infer_contract_types/) & full API in TypeScript
- Using native BigInt instead of large BigNumber libraries: Use native BigInt for improved efficiency compared to using large external BigNumber libraries.
- Custom Output formatters: Format any returned value to be a string, number, BigInt, etc., providing flexibility in handling output data.
Installation
You can install the package either using NPM or using Yarn
Using NPM
npm install web3
Using Yarn
yarn add web3
Getting Started
Prerequisites
Migration Guide
- Migration Guide from Web3.js 1.x to 4.x
Breaking changes are listed in migration guide and its first step for migrating from Web3.js 1.x to 4.x. If there is any question or discussion feel free to ask in discord, and in case of any bug or new feature request open issue or create a pull request for contributions.
Package.json Scripts
Script | Description |
---|
clean | Uses rimraf to remove dist/ |
build | Uses tsc to build package and dependent packages |
lint | Uses eslint to lint package |
lint:fix | Uses eslint to check and fix any warnings |
format | Uses prettier to format the code |
test | Uses jest to run unit tests |
test:integration | Uses jest to run tests under /test/integration |
test:unit | Uses jest to run tests under /test/unit |
Web3.js Packages
We encourage users to use only required individual packages listed in following table, for making lightweight application instead of importing main web3 package, and if you don't need functions from most of the packages that are implicitly included with main web3 package.