A decentralized voting platform that enables users to create proposals and vote securely on-chain using blockchain technology, powered by Base (an Ethereum Layer 2 network).

🚀 Overview The On-Chain Voting dApp demonstrates how blockchain can be used to create transparent, tamper-proof voting systems. Built on Base L2, this application provides a seamless and cost-effective voting experience. Key Features Users can:

🔐 Connect their MetaMask wallet (Base network) 📋 View active proposals in real-time ✅ Cast votes directly on-chain (For/Against) 📊 See live results updated from blockchain events 🆕 Create new proposals for community voting

🏗️ Tech Stack LayerTechnologySmart ContractSolidity, Hardhat, OpenZeppelinFrontendReact (Vite), Tailwind CSSWeb3 LibrariesWagmi + ViemBlockchainBase Sepolia Testnet / Base MainnetDeploymentVercel (frontend), Base (smart contract)

📦 Project Structure on-chain-voting-dapp/ ├── frontend/ # React frontend application │ ├── src/ │ │ ├── components/ # UI components │ │ ├── hooks/ # Custom React hooks │ │ ├── config/ # Wagmi & contract config │ │ └── App.jsx # Main application │ ├── package.json │ └── vite.config.js │ ├── smart-contracts/ # Hardhat smart contract project │ ├── contracts/ │ │ └── Voting.sol # Main voting contract │ ├── scripts/ │ │ └── deploy.js # Deployment script │ ├── test/ │ │ └── Voting.test.js # Contract tests │ ├── hardhat.config.js │ └── package.json │ └── README.md

⚙️ Smart Contract Contract Structure File: contracts/Voting.sol Key Functions FunctionDescriptioncreateProposal(string memory description)Create a new voting proposalvote(uint proposalId, bool support)Vote on a proposal (true = For, false = Against)getProposal(uint proposalId)Retrieve proposal detailsgetAllProposals()Get all proposalshasVoted(uint proposalId, address voter)Check if address has voted Proposal Struct soliditystruct Proposal { uint id; string description; uint forVotes; uint againstVotes; bool executed; address creator; uint createdAt; } Events solidityevent ProposalCreated(uint indexed proposalId, string description, address creator); event Voted(uint indexed proposalId, address indexed voter, bool support);

🛠️ Installation & Setup Prerequisites

Node.js v18+ and npm/yarn MetaMask wallet extension Base Sepolia testnet ETH (faucet)

1️⃣ Clone the Repository bashgit clone https://github.com/yourusername/on-chain-voting-dapp.git cd on-chain-voting-dapp

📜 Smart Contract Setup Install Dependencies bashcd smart-contracts npm install Configure Environment Create .env file: envPRIVATE_KEY=your_wallet_private_key BASE_SEPOLIA_RPC_URL=https://sepolia.base.org BASESCAN_API_KEY=your_basescan_api_key (optional) Compile Contract bashnpx hardhat compile Run Tests bashnpx hardhat test Deploy to Base Sepolia bashnpx hardhat run scripts/deploy.js --network baseSepolia Save the deployed contract address! You'll need it for the frontend. Verify Contract (Optional) bashnpx hardhat verify --network baseSepolia DEPLOYED_CONTRACT_ADDRESS

🎨 Frontend Setup Install Dependencies bashcd frontend npm install Configure Environment Create .env file: envVITE_CONTRACT_ADDRESS=0x_your_deployed_contract_address VITE_BASE_SEPOLIA_RPC=https://sepolia.base.org Update Contract Configuration Edit src/config/contract.js: javascriptexport const VOTING_CONTRACT_ADDRESS = import.meta.env.VITE_CONTRACT_ADDRESS; export const VOTING_ABI = [...]; // Paste ABI from artifacts Run Development Server bashnpm run dev Visit http://localhost:5173 Build for Production bashnpm run build

🌐 Deployment Frontend Deployment (Vercel)

Push code to GitHub Connect repository to Vercel Add environment variables in Vercel dashboard Deploy automatically on push

Smart Contract Deployment Deployed on Base Sepolia Testnet:

Contract Address: 0x... (update after deployment) Explorer: BaseScan Sepolia

For mainnet: bashnpx hardhat run scripts/deploy.js --network base

🧪 Testing Smart Contract Tests bashcd smart-contracts npx hardhat test Test coverage includes:

✅ Proposal creation ✅ Voting functionality ✅ Double-voting prevention ✅ Vote counting accuracy ✅ Event emissions

Frontend Testing bashcd frontend npm run test

📱 Usage Guide

1. Connect Wallet

Click "Connect Wallet" button Approve MetaMask connection Switch to Base Sepolia network if prompted

2. View Proposals

Browse active proposals on the homepage See current vote counts (For/Against)

3. Create Proposal

Click "Create Proposal" Enter proposal description Confirm transaction in MetaMask Wait for confirmation

4. Vote on Proposals

Select a proposal Click "Vote For" or "Vote Against" Confirm transaction Vote is recorded on-chain

🔒 Security Considerations

✅ ReentrancyGuard protection (OpenZeppelin) ✅ One vote per address per proposal ✅ Input validation on all functions ✅ Event logging for transparency ⚠️ Note: This is a demo project. Conduct thorough audits before production use

🌟 Key Smart Contract Features Anti-Double Voting soliditymapping(uint => mapping(address => bool)) public hasVoted;

modifier hasNotVoted(uint proposalId) { require(!hasVoted[proposalId][msg.sender], "Already voted"); _; } Gas Optimization

Uses uint256 instead of smaller types Batched storage operations Efficient event indexing

🛣️ Roadmap

Add proposal expiration time Implement weighted voting (token-based) Add proposal categories/tags Implement delegation Create admin dashboard Multi-chain support IPFS integration for proposal metadata

🤝 Contributing Contributions are welcome! Please follow these steps:

Fork the repository Create a feature branch (git checkout -b feature/AmazingFeature) Commit changes (git commit -m 'Add AmazingFeature') Push to branch (git push origin feature/AmazingFeature) Open a Pull Request

📄 License This project is licensed under the MIT License - see the LICENSE file for details.