Introduction

Hardhat can fork an Ethereum network and run a local simulated Ethereum node based on EthereumJS.

This can be especially useful if you want to interact with the complex decentralized finance (DeFi) contracts deployed on the Ethereum mainnet in a local simulated environment.

Step-by-step

Deploy an Ethereum mainnet node with Chainstack

Deploy the node as described in Join a public network.

Get the RPC endpoint and access credentials of your deployed node as described in View node access and credentials. 

Install Hardhat

Run:

npm install hardhat

Fork the Ethereum mainnet through the Chainstack node at the latest block

Run:

npx hardhat node --fork https://USERNAME:PASSWORD@RPC_ENDPOINT

where

• USERNAME — your Ethereum node access username.
• PASSWORD — your Ethereum node access password.
• RPC_ENDPOINT — your Ethereum node RPC endpoint.

Example:

npx hardhat node --fork https://user-name:pass-word-pass-word-pass-word@nd-123-456-789.p2pify.com

A forked Ethereum mainnet node is now running locally and you can interact with it.

Fork the Ethereum mainnet through the Chainstack node at a specific block

Run:

npx hardhat node --fork https://USERNAME:PASSWORD@RPC_ENDPOINT --fork-block-number BLOCK_NUMBER

where

• USERNAME — your Ethereum node access username.
• PASSWORD — your Ethereum node access password.
• RPC_ENDPOINT — your Ethereum node RPC endpoint.
• BLOCK_NUMBER — the block number at which you want to fork.

Example:

npx hardhat node --fork https://user-name:pass-word-pass-word-pass-word@nd-123-456-789.p2pify.com --fork-block-number 8116664

A forked Ethereum mainnet node is now running locally and you can interact with it.

See also Hardhat documentation.