Deploy a Smart Contract using Hardhat

Prerequisites

Before you begin, ensure you:

Create a Hardhat project

To create an empty Hardhat project:

Create your project directory:

mkdir unifi-smart-contract-tutorial
cd unifi-smart-contract-tutorial

Initialize your Node.js project:
```
npm init
```
Install Hardhat:
```
npm install --save-dev hardhat
```
Initialize the Hardhat project:
```
npx hardhat init
```
In the menu that appears, select Create a JavaScript project and press Enter. Accept all the default values in the questionnaire.

You should now have a sample HardHat project with a Lock contract, that locks funds for a set time, and a few smart contract tests.

note

The default script in ignition/modules/Lock.js locks 1 gwei in the contract upon deployment, you can modify this value in the script.

Deploy the contract

The sample project already includes the deployment script. To deploy on UniFi, you'll just need to make a few modifications to the hardhat.config.js file:

Create a .env file in the root folder with your wallet's private key and RPC Endpoint.
```
PRIVATE_KEY=<your_private_key>
RPC_ENDPOINT=<rpc_https_endpoint>
```
warning
Please do not commit your private keys into source control. Double check that .env is contained in your .gitignore
Download and install dotenv
```
npm i -D dotenv
```

Add UniFi to your hardhat.config.js file. The following example shows how to add a RPC endpoint to the configuration file.

require("@nomicfoundation/hardhat-toolbox");
require("dotenv").config();
const { PRIVATE_KEY, RPC_ENDPOINT } = process.env;

module.exports = {
  solidity: "0.8.27",
  networks: {
    unifi_testnet: {
      url: RPC_ENDPOINT,
      accounts: [PRIVATE_KEY],
    },
  },
};

Deploy your contract.

npx hardhat ignition deploy ./ignition/modules/Lock.js --network <network_name>

In the command:

<network_name> is the name of the network from hardhat.config.js you want to deploy on f.e. unifi_testnet.

Your output should look something like this:

Deployed Addresses

LockModule#Lock - 0xA72022A83654E794B8e9FD7217ADF7378f3e985d

Verify your smart contract

Optionally, you can verify your contract on the network. This makes the source code publicly available.

Verify an already existing contract

To verify a contract, you need to make a few modifications the project.

In your project directory, install hardhat-verify

npm install --save-dev @nomicfoundation/hardhat-verify

Add blockscout url and chain id to the .env file

BLOCKSCOUT_URL=<blockscout_homepage_explorer_url>
CHAIN_ID=<chain_id>

Import hardhat-verify in your hardhat.config.js:

require("@nomicfoundation/hardhat-verify");
require("@nomicfoundation/hardhat-toolbox");
require("dotenv").config();
const { PRIVATE_KEY, RPC_ENDPOINT, BLOCKSCOUT_URL, CHAIN_ID } = process.env;

module.exports = {
  solidity: "0.8.27",
  networks: {
    unifi_testnet: {
      url: RPC_ENDPOINT,
      accounts: [PRIVATE_KEY],
    },
  },
  etherscan: {
    apiKey: {
      unifi_testnet: "empty",
    },
    customChains: [
      {
        network: "unifi_testnet",
        chainId: CHAIN_ID,
        urls: {
          apiURL: `${BLOCKSCOUT_URL}/api`,
          browserURL: BLOCKSCOUT_URL,
        },
      },
    ],
  },
  sourcify: {
    enabled: false,
  },
};

Execute the hardhat verify command:

npx hardhat verify --network <network_name> <contract_address> "constructor_argument_1" "constructor_argument_2" ...

In our example, the full command should look something like this:

npx hardhat verify --network unifi_testnet 0x545D79cAace91bB8A710Ad2ee4e50B01d87bB6Ff 123456

In the command:

<network_name> is the name of the network you want to verify on.
<contract_address> is the address where your contract was deployed.
constructor_argument_1, constructor_argument_2, etc., are the arguments passed to your contract's constructor (if any).

For more contract verification options, refer to the Hardhat verification documentation.

Prerequisites​

Create a Hardhat project​

Deploy the contract​

Verify your smart contract​

Verify an already existing contract​

Prerequisites

Create a Hardhat project

Deploy the contract

Verify your smart contract

Verify an already existing contract