JavaScript / TypeScript

For JavaScript and TypeScript work on Base there are two main library choices: web3.js and ethers.js. Both are actively maintained and both speak standard EVM JSON-RPC, so either connects to Base at https://base.therpc.io/YOUR_API_KEY against chain ID 8453. For new projects we recommend ethers.js v6 — it has stronger TypeScript support and a smaller bundle, which matters for the browser-heavy consumer apps common in the Base ecosystem.

Both web3.js and ethers.js are actively maintained and production-ready on Base. For new Base projects, prefer ethers.js v6: its first-class TypeScript support and smaller bundle size make it the better default, especially for front-end dApps.

Web3.js

web3.js is the original and most widely used JavaScript API for EVM chains, and it works on Base unchanged. Install it with npm install web3, then instantiate a client by passing your Base endpoint to the constructor: new Web3('https://base.therpc.io/YOUR_API_KEY'). From there, web3.eth exposes balance, transaction, and contract calls against chain ID 8453.

1import Web3 from 'web3';
2const web3 = new Web3('https://base.therpc.io/YOUR_API_KEY');
3 
4// Get balance
5const getBalance = async (address) => {
6	const balance = await web3.eth.getBalance(address);
7	const balanceInEth = web3.utils.fromWei(balance, 'ether');
8	return balanceInEth;
9};
10 
11// Send transaction
12const sendTransaction = async (from, to, value) => {
13	const tx = {
14		from,
15		to,
16		value: web3.utils.toWei(value, 'ether'),
17	};
18	return await web3.eth.sendTransaction(tx);
19};

• GitHub: https://github.com/web3/web3.js
• Docs: https://web3js.readthedocs.io/
• Key features: complete coverage of the Base JSON-RPC API, WebSocket subscriptions, contract interactions, ENS support, and a large community

Ethers.js

ethers.js is a modern, compact library with first-class TypeScript support, which makes it a natural fit for Base front-ends. Install it with npm install ethers, then connect by passing your Base endpoint to a JsonRpcProvider: new ethers.JsonRpcProvider('https://base.therpc.io/YOUR_API_KEY'). That provider handles reads on chain ID 8453, and you pair it with a Wallet to sign and send transactions.

1import { ethers } from 'ethers';
2const provider = new ethers.JsonRpcProvider('https://base.therpc.io/YOUR_API_KEY');
3 
4// Get balance
5const getBalance = async (address) => {
6	const balance = await provider.getBalance(address);
7	return ethers.formatEther(balance);
8};
9 
10// Send transaction
11const sendTransaction = async (wallet, to, value) => {
12	const tx = await wallet.sendTransaction({
13		to,
14		value: ethers.parseEther(value),
15	});
16	return await tx.wait();
17};

• GitHub: https://github.com/ethers-io/ethers.js/
• Docs: https://docs.ethers.org/
• Key features: first-class TypeScript support, smaller bundle size, strong security defaults, ENS support, and extensive test coverage — all available on Base

TypeScript Support

Both web3.js and ethers.js ship their own type definitions, so you get full typing for your Base code without installing any @types/* package. In practice that means IDE autocompletion for every eth method, compile-time checking that catches a malformed transaction object before it ever hits the Base node, and type signatures that document the API as you write.

1import { BigNumber } from 'ethers';
2 
3interface TransactionData {
4	to: string;
5	value: BigNumber;
6	gasLimit?: BigNumber;
7}
8 
9const createTransaction = async (data: TransactionData) => {
10	// Your implementation
11};

Node.js Usage

Both libraries run in Node.js for backend Base services — indexers, bots, and webhook handlers — and support either CommonJS require() or ESM import, so they drop into whatever module system your project already uses.

1// Web3.js in Node.js
2const Web3 = require('web3');
3const web3 = new Web3('https://base.therpc.io/YOUR_API_KEY');
4 
5// Ethers.js in Node.js
6const { ethers } = require('ethers');
7const provider = new ethers.JsonRpcProvider('https://base.therpc.io/YOUR_API_KEY');

Browser Usage

In the browser, use ES module imports and let a bundler like webpack or Vite package the library for your Base dApp. When you need a user's wallet — MetaMask, Coinbase Wallet, or another injected provider common in the Base ecosystem — wrap it with new ethers.BrowserProvider(window.ethereum) so the user signs transactions with their own keys while your JsonRpcProvider handles read traffic.

1// Using ES modules
2import { Web3 } from 'web3';
3// or
4import { ethers } from 'ethers';
5 
6// Using window.ethereum (MetaMask)
7const provider = new ethers.BrowserProvider(window.ethereum);