Blockchain Development Programming Tutorials, Guides & Best Practices

In this step, we will use Ethers.js to query the balance of an ERC-20 token for a specific Ethereum address.

const ethers = require('ethers');

// Replace with your Infura or other Ethereum node provider URL
const provider = new ethers.JsonRpcProvider('https://mainnet.infura.io/v3/YOUR_INFURA_PROJECT_ID');

// Replace with the ERC-20 token contract address (e.g., USDT, DAI)
const contractAddress = '0xTokenContractAddress';

// Replace with the wallet address you want to query
const walletAddress = '0xYourEthereumAddress';

// ERC-20 token ABI (just the balanceOf function)
const abi = [
    'function balanceOf(address owner) view returns (uint256)'
];

// Create a contract instance
const contract = new ethers.Contract(contractAddress, abi, provider);

async function getTokenBalance() {
    try {
        // Query the balance
        const balance = await contract.balanceOf(walletAddress);

        // Convert balance to a human-readable format (tokens usually have 18 decimals)
        const formattedBalance = ethers.utils.formatUnits(balance, 18);

        console.log(`Token Balance: ${formattedBalance}`);
    } catch (error) {
        console.error('Error fetching token balance:', error);
    }
}

// Call the function to get the token balance
getTokenBalance();

Before you begin, you’ll need the following:

• Node.js installed on your machine.
• A basic understanding of JavaScript.
• An Etherscan API key (explained below).

Introduction

In this tutorial, we will learn how to track newly created tokens on the Ethereum blockchain. With the rapid growth of decentralized finance (DeFi) and non-fungible tokens (NFTs), keeping an eye on newly created tokens can be valuable for investors, developers, and enthusiasts. We will use Etherscan's API to monitor token creation events and Web3.js to interact with the Ethereum network.