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Understanding and Using the Etherscan API to Query Blockchain Data

Tutorial October 24, 2024

const axios = require('axios');

// Replace this with your actual Etherscan API key
const apiKey = 'YOUR_ETHERSCAN_API_KEY';

// Replace this with the Ethereum address you want to query
const address = '0xYourEthereumAddress';

// Replace this with the contract address of the ERC-20 token
const contractAddress = '0xYourTokenContractAddress';

// Etherscan API URL to fetch the ERC-20 token balance
const url = `https://api.etherscan.io/api?module=account&action=tokenbalance&contractaddress=${contractAddress}&address=${address}&tag=latest&apikey=${apiKey}`;

async function getTokenBalance() {
  try {
    // Make the API request to Etherscan
    const response = await axios.get(url);
    const tokenBalance = response.data.result;

    // Log the token balance (Note: Token balances are often in very small denominations)
    console.log(`Token Balance: ${tokenBalance}`);
  } catch (error) {
    console.error('Error fetching token balance:', error);
  }
}

// Call the function to get the token balance
getTokenBalance();
  • Replace 'YOUR_ETHERSCAN_API_KEY' with your Etherscan API key.
  • Replace '0xYourEthereumAddress' with the address you want to query.
  • Replace '0xYourTokenContractAddress' with the ERC-20 token's contract address (e.g., USDT or DAI token contract).
  • This script queries the ERC-20 token balance for a specific Ethereum address.