Learn Ethersjs - 10 Code Examples & CST Typing Practice Test

Ethers.js is a lightweight, complete JavaScript library for interacting with the Ethereum blockchain, providing tools for wallet management, smart contract interaction, and blockchain communication.

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Ethers.js Simple Smart Contract Interaction Ethers.js Check Balance Ethers.js Send Ether Ethers.js Deploy Contract Ethers.js Listen to Events Ethers.js Read-Only Contract Call Ethers.js Estimate Gas Ethers.js Batch Call Example Ethers.js Sign Message Ethers.js Verify Signature

Learn ETHERSJS with Real Code Examples

Updated Nov 25, 2025

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Code Sample Descriptions

Ethers.js Simple Smart Contract Interaction

const { ethers } = require('ethers')

// Connect to local Ethereum node
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')

// Contract ABI and address
const abi = [...]
const address = '0xYourContractAddress'
const contract = new ethers.Contract(address, abi, provider)

// Read value from contract
async function main() {
    const value = await contract.getValue()
    console.log('Contract value:', value)

    // Send transaction to contract
    const signer = provider.getSigner(0)
    const tx = await contract.connect(signer).setValue(42)
    await tx.wait()
    console.log('Transaction complete')
}

main()

A minimal example showing how to connect to Ethereum and interact with a deployed smart contract using Ethers.js.

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Ethers.js Check Balance

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')

async function main() {
    const balance = await provider.getBalance('0xYourAddress')
    console.log('Balance:', ethers.formatEther(balance))
}

main()

Connects to Ethereum and prints the Ether balance of an account.

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Ethers.js Send Ether

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')

async function main() {
    const signer = provider.getSigner(0)
    const tx = await signer.sendTransaction({
        to: '0xRecipientAddress',
        value: ethers.parseEther('0.1')
    })
    await tx.wait()
    console.log('Ether sent')
}

main()

Send Ether from one account to another using Ethers.js.

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Ethers.js Deploy Contract

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const signer = provider.getSigner(0)

async function main() {
    const factory = new ethers.ContractFactory(abi, bytecode, signer)
    const contract = await factory.deploy()
    await contract.deployed()
    console.log('Contract deployed at:', contract.address)
}

main()

Deploy a simple contract using Ethers.js and a signer.

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Ethers.js Listen to Events

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const contract = new ethers.Contract('0xYourContractAddress', abi, provider)

contract.on('ValueChanged', (newValue) => {
    console.log('Value changed:', newValue)
})

Subscribe to a contract event and log it in real-time.

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Ethers.js Read-Only Contract Call

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const contract = new ethers.Contract('0xYourContractAddress', abi, provider)

async function main() {
    const data = await contract.getData()
    console.log('Contract data:', data)
}

main()

Perform a read-only call to fetch contract data without sending a transaction.

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Ethers.js Estimate Gas

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const contract = new ethers.Contract('0xYourContractAddress', abi, provider)

async function main() {
    const gasEstimate = await contract.estimateGas.setValue(42)
    console.log('Estimated gas:', gasEstimate)
}

main()

Estimate gas usage for a contract method call.

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Ethers.js Batch Call Example

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const contract = new ethers.Contract('0xYourContractAddress', abi, provider)

async function main() {
    const value1 = await contract.getValue()
    const value2 = await contract.getAnotherValue()
    console.log('Values:', value1, value2)
}

main()

Use Ethers.js to make multiple contract calls in sequence.

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Ethers.js Sign Message

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')

async function main() {
    const signer = provider.getSigner(0)
    const signature = await signer.signMessage('Hello Ethereum')
    console.log('Signature:', signature)
}

main()

Sign a message with an Ethereum account using Ethers.js.

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Ethers.js Verify Signature

const { ethers } = require('ethers')

const message = 'Hello Ethereum'
const signature = '0xSignatureHere'
const signerAddress = ethers.verifyMessage(message, signature)
console.log('Signer address:', signerAddress)

Verify an Ethereum signature using Ethers.js.

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Frequently Asked Questions about Ethersjs

What is Ethersjs?

Ethers.js is a lightweight, complete JavaScript library for interacting with the Ethereum blockchain, providing tools for wallet management, smart contract interaction, and blockchain communication.

What are the primary use cases for Ethersjs?

Interacting with Ethereum smart contracts. Wallet management and transaction signing. Connecting to Ethereum nodes (mainnet, testnets). Building frontend dApps. Reading blockchain state and events

What are the strengths of Ethersjs?

Simple and easy-to-learn API. Modular and tree-shakable for frontend use. Secure default handling of keys and signing. TypeScript support improves development safety. Actively maintained and widely adopted

What are the limitations of Ethersjs?

Ethereum-only (doesn’t natively support other chains without EVM compatibility). Requires understanding of blockchain concepts. Some advanced features (ENS, multicall) need extra modules. No native transaction batching support. Limited UI helpers (requires integration with other frontend libraries)

How can I practice Ethersjs typing speed?

CodeSpeedTest offers 10+ real Ethersjs code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.

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Code Sample Descriptions

Ethers.js Simple Smart Contract Interaction

const { ethers } = require('ethers')

// Connect to local Ethereum node
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')

// Contract ABI and address
const abi = [...]
const address = '0xYourContractAddress'
const contract = new ethers.Contract(address, abi, provider)

// Read value from contract
async function main() {
    const value = await contract.getValue()
    console.log('Contract value:', value)

    // Send transaction to contract
    const signer = provider.getSigner(0)
    const tx = await contract.connect(signer).setValue(42)
    await tx.wait()
    console.log('Transaction complete')
}

main()

A minimal example showing how to connect to Ethereum and interact with a deployed smart contract using Ethers.js.

Let’s Try →

Ethers.js Check Balance

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')

async function main() {
    const balance = await provider.getBalance('0xYourAddress')
    console.log('Balance:', ethers.formatEther(balance))
}

main()

Connects to Ethereum and prints the Ether balance of an account.

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Ethers.js Send Ether

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')

async function main() {
    const signer = provider.getSigner(0)
    const tx = await signer.sendTransaction({
        to: '0xRecipientAddress',
        value: ethers.parseEther('0.1')
    })
    await tx.wait()
    console.log('Ether sent')
}

main()

Send Ether from one account to another using Ethers.js.

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Ethers.js Deploy Contract

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const signer = provider.getSigner(0)

async function main() {
    const factory = new ethers.ContractFactory(abi, bytecode, signer)
    const contract = await factory.deploy()
    await contract.deployed()
    console.log('Contract deployed at:', contract.address)
}

main()

Deploy a simple contract using Ethers.js and a signer.

Let’s Try →

Ethers.js Listen to Events

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const contract = new ethers.Contract('0xYourContractAddress', abi, provider)

contract.on('ValueChanged', (newValue) => {
    console.log('Value changed:', newValue)
})

Subscribe to a contract event and log it in real-time.

Let’s Try →

Ethers.js Read-Only Contract Call

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const contract = new ethers.Contract('0xYourContractAddress', abi, provider)

async function main() {
    const data = await contract.getData()
    console.log('Contract data:', data)
}

main()

Perform a read-only call to fetch contract data without sending a transaction.

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Ethers.js Estimate Gas

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const contract = new ethers.Contract('0xYourContractAddress', abi, provider)

async function main() {
    const gasEstimate = await contract.estimateGas.setValue(42)
    console.log('Estimated gas:', gasEstimate)
}

main()

Estimate gas usage for a contract method call.

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Ethers.js Batch Call Example

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')
const contract = new ethers.Contract('0xYourContractAddress', abi, provider)

async function main() {
    const value1 = await contract.getValue()
    const value2 = await contract.getAnotherValue()
    console.log('Values:', value1, value2)
}

main()

Use Ethers.js to make multiple contract calls in sequence.

Let’s Try →

Ethers.js Sign Message

const { ethers } = require('ethers')
const provider = new ethers.JsonRpcProvider('http://127.0.0.1:8545')

async function main() {
    const signer = provider.getSigner(0)
    const signature = await signer.signMessage('Hello Ethereum')
    console.log('Signature:', signature)
}

main()

Sign a message with an Ethereum account using Ethers.js.

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Ethers.js Verify Signature

const { ethers } = require('ethers')

const message = 'Hello Ethereum'
const signature = '0xSignatureHere'
const signerAddress = ethers.verifyMessage(message, signature)
console.log('Signer address:', signerAddress)

Verify an Ethereum signature using Ethers.js.

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Frequently Asked Questions about Ethersjs

What is Ethersjs?

Ethers.js is a lightweight, complete JavaScript library for interacting with the Ethereum blockchain, providing tools for wallet management, smart contract interaction, and blockchain communication.

What are the primary use cases for Ethersjs?

Interacting with Ethereum smart contracts. Wallet management and transaction signing. Connecting to Ethereum nodes (mainnet, testnets). Building frontend dApps. Reading blockchain state and events

What are the strengths of Ethersjs?

What are the limitations of Ethersjs?

How can I practice Ethersjs typing speed?

CodeSpeedTest offers 10+ real Ethersjs code examples for typing practice. You can measure your WPM, track accuracy, and improve your coding speed with guided exercises.