Counter Smart Contract - Hardhat

Build & Deploy a Counter Contract on Kite AI using Hardhat

What is Hardhat?

Hardhat is a local development environment for Ethereum-style (EVM) blockchains. It lets you: • Compile, test, and deploy contracts from your machine. • Script deployments and verifications (great for CI/CD). • Fork networks locally, run a local node, and debug with stack traces and console logging. • Use a rich plugin ecosystem (ethers.js, Etherscan-style verification, gas reporters, coverage, etc.).

In this section, we will go over Hardhat workflow:

- Set up & Scaffold project
- Write contract
- Compile
- Configure network
- Deploy via script
- Interact via console/scripts

Prerequisites:

•	Node.js 18+ and npm (or pnpm/yarn)
•	A funded wallet (for Kite testnet/mainnet)
•	MetaMask (optional -  recommended for managing keys)
•	Git (recommended)

1. Create a Hardhat Project:

• Create and enter a new folder:

  mkdir kite-counter-hardhat && cd kite-counter-hardhat

• Initialize a Node project:

  npm init -y

• Install Hardhat and tooling:

  npm install --save-dev hardhat @nomicfoundation/hardhat-toolbox dotenv

• Scaffold a Hardhat project (choose “Create a TypeScript project” when prompted):

  npx hardhat

This creates a hardhat.config.ts, sample tests, and a basic project structure.

2. Add Envrironment variable:

Create a .env file in the project root

touch.env

Put your secrets and Kite endpoints in it (replace placeholders):

Wallet private key (no 0x prefix or with 0x — Hardhat supports either):

PRIVATE_KEY=0xYOUR_PRIVATE_KEY_HERE

Kite AI network (testnet or mainnet) RPC:

KITE_RPC_URL=https://rpc-testnet.gokite.ai/

Chain ID (number):

KITE_CHAIN_ID=2368

KITE EXPLORER URL:

KITE_EXPLORER_BROWSER_URL=https://testnet.kitescan.ai/ 

.gitignore (ensure secrets aren’t committed):

node_modules
.env
cache
artifacts
typechain-types

3. Configure hardhat

Open hardhat.config.ts and replace with:

import { HardhatUserConfig } from "hardhat/config";
import "@nomicfoundation/hardhat-toolbox";
import * as dotenv from "dotenv";
dotenv.config();

const PRIVATE_KEY = process.env.PRIVATE_KEY || "";
const KITE_RPC_URL = process.env.KITE_RPC_URL || "";
const KITE_CHAIN_ID = process.env.KITE_CHAIN_ID ? Number(process.env.KITE_CHAIN_ID) : undefined;

const config: HardhatUserConfig = {
  solidity: {
    version: "0.8.20",
    settings: { optimizer: { enabled: true, runs: 200 } },
  },
  networks: {
    // Rename to "kite" or "kiteMainnet" as you prefer
    kiteTestnet: {
      url: KITE_RPC_URL,
      chainId: KITE_CHAIN_ID,
      accounts: PRIVATE_KEY ? [PRIVATE_KEY] : [],
    },
  },
  // Optional: If Kite explorer is Etherscan-compatible, enable this
  etherscan: {
    apiKey: {
      kiteTestnet: process.env.EXPLORER_API_KEY || "",
    },
    customChains: [
      {
        network: "kiteTestnet",
        chainId: KITE_CHAIN_ID || 0,
        urls: {
          apiURL: process.env.KITE_EXPLORER_API_URL || "",
          browserURL: process.env.KITE_EXPLORER_BROWSER_URL || "",
        },
      },
    ],
  },
};

export default config;

4. Write the Counter Contract

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

contract Counter {
    uint256 public count;

    function increment() public {
        count += 1;
    }

    function decrement() public {
        require(count > 0, "Counter cannot be negative");
        count -= 1;
    }

    function getCount() public view returns (uint256) {
        return count;
    }
}

5. Compile

npx hardhat compile

6. Write a Deployment Script

Create scripts/deploy.ts:

import { ethers } from "hardhat";

async function main() {
  const Counter = await ethers.getContractFactory("Counter");
  const counter = await Counter.deploy();
  await counter.waitForDeployment();

  const address = await counter.getAddress();
  console.log("Counter deployed to:", address);
}

main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

7. Fund Your Deployer & Add the Network (MetaMask)

- Add the Kite AI network to MetaMask using the same RPC URL and Chain ID you placed in .env.
- Fund the deployer address with KITE (or test KITE on testnet) to cover gas.
- Ensure the private key in .env matches the funded account.

8. Deploy to Kite AI

npx hardhat run scripts/deploy.ts --network kiteTestnet

Output example: Counter deployed to: 0xABCDEF1234567890abcdef1234567890ABCDEF12

Important - Copy and save this address on your notepad.

9. Verify if deployment went through successfully

-  VIsit the explorer site - https://testnet.kitescan.ai/ 
- Copy and paste the deplotment contract from previous step on the search bar
- Look up the deployer details ( your public key) and contract details on the results page. 

10. Troubleshooting

•	Insufficient funds for gas * price + value - Fund your deployer wallet with KITE (or test KITE).
•	Invalid sender / nonce too low - Reset your account nonce in MetaMask or wait for pending txs to clear; you can also specify a higher nonce manually.
•	Unsupported chainId - Ensure KITE_CHAIN_ID in .env matches the network’s actual chain ID.
•   No PRIVATE_KEY set - Add PRIVATE_KEY to .env and restart your command.

11. Security & Best Practices

•	Never commit secrets (.env in .gitignore).
•	Use a deployment-only wallet with limited funds.
•	For teams, consider multi-sig for production keys and use a deployer bot with restricted permissions.
•	Pin exact versions in package.json to ensure reproducibility.
•	Keep compiler optimizations consistent across environments.

If you wish to integrate this deployed contract to a front-end with a user interface, visit the below link and follow the steps:

• https://docs.gokite.ai/blockchain-development/sample-dapps-built-on-kite/counter-dapp