Sending Transactions to Forks

Working with Hardhat

Tenderly Forks expose a Fork URL you can use to define a tenderly network in the Hardhat user config. When running Hardhat scripts and tasks, by specifying --network tenderly, you forward all transactions sent through Ethers to a Fork for a simulation.

Here’s how to configure Hardhat to use a Tenderly Fork as a network:

// File: hardhat.config.ts
// -- snip --
const config: HardhatUserConfig = {
  solidity: "0.8.9",
  networks: {
    // -- snip --
+   tenderly: {
+     chainId: 3, // chain you forked
+     url: "FORK-URL",
+   },
  }
  // -- snip --
}
export default config

The placeholder FORK-URL is the JSON-RPC URL exposed by the Fork. It uses the following format:https://rpc.tenderly.co/fork/{FORK_ID}. You can find the JSON-RPC URL in the Dashboard.

Your existing Hardhat scripts should work as expected.

import { ethers } from 'hardhat';
 
async function main() {
  // show accounts created on the fork
  console.log(await ethers.provider.listAccounts());
  // ... etc
}

Working with Ethers.js

If you want to connect to a Tenderly Fork using Ethers, it’s sufficient to create a JsonRpcProvider instance:

const provider = new JsonRpcProvider(FORK_URL);
const myContract = new ethers.Contract(ADDRESS, ABI, provider.getSigner());
 
// 10 accounts with balance 100 available
const accounts = await provider.listAccounts();
const signers = accounts.map(acc => provider.getSigner(acc));

Any transactions sent to myContract will be directed to and simulated on a Fork.

Controlling the Fork

To fully control all aspects of simulations happening on a Fork, such as account balances, mined blocks, or even the passage of time, explore the Fork Customization via API guide.