How can I connect to Hedera Testnet using web3.js or ethers.js?

Question

​ I would like to interact with the Hedera Testnet using web3.js or ethers.js. How can I do this? ​ I have previously interacted with Hedera Testnet using hedera-sdk-js, for example using the following code: ​

import {
    AccountBalanceQuery, 
    Client
} from "@hashgraph/sdk";
​
const client = new Client({
    network: "testnet"
});
​
const accountId = '0.0.3996280';
const balance = await new AccountBalanceQuery()
    .setAccountId(accountId)
    .execute(client);
    
console.log(
    `Balance of ${accountId} in Tinybars:`,
    balance.hbars.toTinybars().toString(10)
);
​

​ How can I do the equivalent of the above in web3.js/ ethers.js?

Answer 1

To connect using ethers.js

(1) First, obtain an RPC endpoint URL, which is detailed over at How can I connect to Hedera Testnet over RPC?. ​ Once you have gotten that, substitute ${RPC_URL} in the code examples below with that value.

(2)​ Install ethers.js: ​

npm install ethers@v5

(3)​ Then use the following script to establish a connection to the RPC endpoint using ethers.providers.JsonRpcProvider, and query eth_blockNumber with it: ​

import { ethers } from 'ethers';
​
const web3Provider = new ethers.providers.JsonRpcProvider({
    url: '${RPC_URL}',
    headers: {
        'Access-Control-Allow-Origin': '*',
    },
});
​
async function main() {
    web3Provider.getBlockNumber()
        .then((blockNumber) => {
            console.log('block number', blockNumber);
        })
        .catch(console.error);
​
    web3Provider.getBalance(
        '0x00000000000000000000000000000000003cfa78')
        .then((balance) => {
            console.log('balance', balance.toBigInt());
        })
        .catch(console.error);
}
​
main();
​

​