How to use existing ERC20 tokens in local testnet?

Question

I am running a local Hardhat network to test my contracts. I want my contract to eventually be able to swap existing ERC20 tokens, for example WETH/USDC on Uniswap.

Is there a way to test this in my local Hardhat network?

As a complete beginner to the world of blockchain, I would very much appreciate your answers!

Answer 1

You need to enable mainnet forking in Hardhat network to be able to access a copy of mainnet-deployed contracts in your local running instance. You could enable mainnet forking with the following Hardhat config:

const config = {
  networks: {
    hardhat: {
      chainId: 1337,
      forking: {
        enabled: true,
        url: `https://eth-mainnet.alchemyapi.io/v2/${ALCHEMY_KEY}`,
      },
    },
  },
}