Understanding eth_getBalance on Polygon: A Developer's Guide

Polygon's eth_getBalance API method retrieves the balance of any Polygon account in Wei (the smallest denomination of ether). This essential tool enables developers to verify account balances, monitor funds, and display financial information within applications.

How eth_getBalance Works

The method returns the balance stored at a specific Polygon address at a given block height. Key components:

Parameters

• address: The Polygon wallet address to query

• block parameter: Specifies which block to reference:

  • latest: Current blockchain state
  • earliest: Genesis block
  • pending: Unconfirmed transactions

Response

• quantity: The balance in Wei (as hexadecimal)

Practical Implementation

Web3.js Code Example

const Web3 = require("web3");
const NODE_URL = "CHAINSTACK_NODE_URL";
const web3 = new Web3(NODE_URL);

const accountAddress = '0xB18614D1e3A3B67A6E0c83Be98AC04157b674083';
const minimumBalance = 10000000000000000000; // 10 Matic in wei

async function checkBalance(address) {
  const balance = await web3.eth.getBalance(address, 'latest');
  return balance;
}

async function fillUp(balance) {
  const minimumConverted = web3.utils.fromWei(String(minimumBalance), 'ether');
  if (balance < minimumBalance) {
    console.log(`The balance of the account ${accountAddress} is below ${minimumConverted} Matic.`);
    console.log(`Sending more funds...`)
    // Additional funding logic here
  } else {
    console.log(`The balance of the account ${accountAddress} is above ${minimumConverted} Matic.`);
  }
}

async function main() {
  const balance = await checkBalance(accountAddress);
  const balanceInMatic = web3.utils.fromWei(balance, 'ether');
  console.log(`Current balance: ${balanceInMatic} Matic \n`);
  await fillUp(balance);
}

main();

This script demonstrates automatic balance monitoring with:

• Real-time balance checks
• Minimum balance thresholds
• Conditional funding alerts

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Core Use Cases

1. Funds Monitoring: Track account balances in real-time
2. Automated Replenishment: Maintain minimum balances
3. Financial Dashboards: Display current holdings

Frequently Asked Questions

What's the difference between Wei and MATIC?

Wei is the smallest unit (1 MATIC = 10^18 Wei), used for precise calculations. The fromWei method converts balances to user-friendly MATIC values.

How often should I check balances?

For automated systems, checks every 5-15 minutes typically balance accuracy with node request limits.

Can I use eth_getBalance with smart contracts?

Yes, but it only returns the native MATIC balance, not ERC-20 token balances which require separate contract calls.

👉 Master Polygon development with our advanced guide

Best Practices

• Cache results to reduce node requests
• Handle errors for network instability