hardhat-etherscan-contract

Hardhat plugin that fetches verified contract ABI and source code from Etherscan.

What

This plugin adds extra features on top of @nomiclabs/hardhat-ethers and allows creating contract instances without manually downloading ABI: getVerifiedContractAt('<address>'). It supports Mainnet, BSC, and most testnets. It can also retrieve full source code of verified contracts using getContractCodeAt(<address>).

Installation

// npm install --save-dev hardhat-etherscan-contract

And add the following statement to your hardhat.config.js:

require("hardhat-etherscan-contract");

Or, if you are using TypeScript, add this to your hardhat.config.ts:

import "hardhat-etherscan-contract";

Tasks

This plugin adds fetchSource task that retrieves source code of a verified contract located on --address. Sources are stored to default contracts location, unless explicit --path is specified. Using --all flag allows to save all dependencies tree of the requested contract.

Environment extensions

This object has adds some extra hardhat-etherscan-contract specific functionalities by adding new extra fields to hre

Helpers

These helpers are added to the hre object:

export async function getVerifiedContractAt(
  hre: HardhatRuntimeEnvironment,
  address: string,
  signer?: ethers.Signer
): Promise<ethers.Contract>;

export async function getContractCodeAt(
  hre: HardhatRuntimeEnvironment,
  address: string,
  chainId?: number
): Promise<GetSourceCodeReponse[]>;

Usage

You need to add the following Etherscan config to your hardhat.config.js file. Etherscan API key is optional but without it Etherscan allows only 1 request per 5 seconds.

module.exports = {
  networks: {
    mainnet: { ... }
  },
  etherscan: {
    // Your API key for Etherscan
    // Obtain one at https://etherscan.io/
    apiKey: "YOUR_ETHERSCAN_API_KEY"

    // Keys can be set separately for each network, the currently loaded network by hardhat will be used
    // apiKey: {
    //   mainnet: "",
    //   polygon: ""
    // }
  }
};

Then use the function:

const contract = await hre.getVerifiedContractAt('<address>');

It requires only contract address and will fetch the ABI for the contract automatically from Etherscan