Creating a Hardhat Runtime Environment programmatically

The Hardhat Runtime Environment can be created programmatically, which is useful for scripting, testing, and having multiple instances of it at the same time.

Creating a Hardhat Runtime Environment with a configuration file

You can create a Hardhat Runtime Environment using a configuration file like this:

import {
  createHardhatRuntimeEnvironment,
  resolveHardhatConfigPath,
  importUserConfig,
} from "hardhat/hre";

const configPath = await resolveHardhatConfigPath();
const config = await importUserConfig(configPath);
const hre = await createHardhatRuntimeEnvironment(config, {
  config: configPath,
  // other global options, like network
});

In this example, resolveHardhatConfigPath finds the configuration file path using the same logic as the Hardhat CLI. You can use an absolute path instead.

createHardhatRuntimeEnvironment takes a configuration object as its first argument, followed by an object with Global Options. It also accepts an optional third parameter with the path to the project root. You’ll rarely need it, but it’s useful for creating a Hardhat Runtime Environment in a different directory.

Creating a Hardhat Runtime Environment without a configuration file

You can also create a Hardhat Runtime Environment with an in-memory configuration object that doesn’t come from a file:

import { defineConfig } from "hardhat/config";
import { createHardhatRuntimeEnvironment } from "hardhat/hre";

const config = defineConfig({
  solidity: "0.8.28",
});

const hre = await createHardhatRuntimeEnvironment(config, {
  // optional object with global options, but no config path
});

The only differences here are that you define the config inline instead of using a file, and that you don’t pass the config Global Option to createHardhatRuntimeEnvironment.

Learn more

To learn more about the Hardhat Runtime Environment, read the Hardhat Runtime Environment documentation.

For configuration details, see the Configuration reference.