web3js

With Web3.js, you can

Deploy and interact with smart contracts as TS/JS objects

Subscribe to specific on-chain or smart contract events

Interact with the Ethereum Name Service (ENS)

Create and import accounts, sign data and transactions

Get block and state information from Ethereum nodes

Have access to utilities with built-in helpers for Ethereum dApps and web3 packages

Web3.js Features

Abstractions over the JSON-RPC API

Simplifying interaction for your Developer Experience.

Dynamic contract types and full API in TypeScript

Enforced with strict types for enhanced security and safety.

Most efficient ABI Encoder & Decoder

Include only what you need during bundling for optimized performance.

ESM and CJS module builds

Support for both ECMAScript module and CommonJS module builds for flexible integration with various project setups.

Custom Output formatters

Format any returned value to be a string, number, BigInt, etc., providing flexibility in handling output data.

Language Aligned

to the official Ethereum terminology

Step 1. Import Web3 module.


  import {Web3} from "web3";

  // set a provider in the sepolia testnet using node rpc url
  const web3 = new Web3("https://rpc.sepolia.org");
  
  // interacting with the smart contract
  const abi = [
      {
      outputs: [
          {
          internalType: "uint256",
          name: "randomNo",
          type: "uint256",
          },
      ],
      name: "generateRandomNumber",
      stateMutability: "nonpayable",
      type: "function",
      },
  ] as const;
  
  const address = "0xA36432F7B12f160F685717c4Ab12EB883a682810";
  
  // create a new contract object, providing the ABI and address
  const contract = new web3.eth.Contract(abi, address);
  
  // using contract.methods to get value
  contract.methods
      .generateRandomNumber()
      .call()
      .then(console.log);

Step 2. Initialize a Web3 provider.


  import {Web3} from "web3";
  
  // set a provider to the sepolia testner using node rpc url
  const web3 = new Web3("wss://sepolia.infura.io/ws/v3/API_KEY");

  // interacting with the smart contract
  const abi = [
    {
      inputs: [
        {
          internalType: "uint256",
          name: "randomNo",
          type: "uint256",
        },
      ],
      name: "RandomNo",
      type: "event",
    },
  ] as const;

  const address = "0xA36432F7B12f160F685717c4Ab12EB883a682810";

  // create a new contract object, providing the ABI and address
  const contract = new web3.eth.Contract(abi, address);

// using contract.methods to get value
const subscription = contract.events.RandomNo()
subscription.on("data", console.log); // new value every time the event is emitted

Step 3. Start querying; i.e, current block number.


  import {Web3} from "web3"
  
  // set a provider such as using infura
  const web3 = new Web3("https://rpc.sepolia.org") 
  
  // Get the balance of an Ethereum address
  web3.eth.getBalance("0xF8561Dc64E577B0CF53dd3FC11329e80B1A8343e").then(console.log) // result: 1.000.000 eth
  
  // Get the latest block number
   web3.eth.getBlockNumber().then(console.log) // result: BigInt(xxx)

Testimonials

“At Chainstack, Web3.js has been instrumental in developing our RPC API documentation and tutorials. Its robust features and seamless integration allow us to showcase use cases effectively, enabling developers to leverage the full potential of blockchain technology quickly. Web3.js is a foundational tool that enhances our ability to support developers in building scalable and innovative applications on multiple blockchains.”

“Developing the Namespace ENS plugin for Web3.js was a smooth experience. Developer docs are concise and easy to follow, and their SDK made the process even more frictionless. On top of that, the DevRel team was always available to provide any support if needed.”

“We have been relying on Web3.js to build DeFi Saver since 2020. With us having built a lot of custom infra in-house, Web3.js had been a great tool for this purpose. The API has been stable and it provided us enough visibility and control over the entire stack. It has also been here for a while and all the tooling around it is stable and ready, so theres hardly ever any issues.”

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Why Web3.js?