🎲 Foundry Smart Contract Lottery

A decentralized lottery smart contract built with Solidity and Foundry, powered by:

• 🔐 Chainlink VRF v2.5 (Verifiable Randomness)
• 🤖 Chainlink Automation (Keepers)
• 🧪 Unit Testing
• 🔁 Fuzz Testing

The contract automatically selects a provably random winner after a fixed time interval.

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🚀 Features

• Users can enter the raffle by paying an entrance fee
• Automated winner selection using Chainlink Automation
• Provably random winner using Chainlink VRF
• Secure state machine (OPEN → CALCULATING → OPEN)
• Fully tested with Foundry
• Fuzz testing included
• Deployment & interaction scripts included

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🛠 Tech Stack

• Solidity ^0.8.x
• Foundry
• Chainlink VRF v2.5
• Chainlink Automation
• Sepolia Testnet

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📂 Project Structure

foundry-smart-contract-lottery/ │ ├── src/ # Smart contracts ├── script/ # Deployment & interaction scripts ├── test/ # Unit & fuzz tests ├── foundry.toml # Foundry config ├── .gitignore └── README.md

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⚙️ Installation

1️⃣ Install Foundry

If you don’t have Foundry installed:

curl -L https://foundry.paradigm.xyz | bash
source ~/.bashrc
foundryup

2️⃣ Clone the Repository git clone https://github.com/vedantghate18/foundry-smart-contract-lottery.git

3️⃣ Install Dependencies forge install

🔐 How It Works

1. Users enter the raffle by sending ETH.

2. After a fixed interval, Chainlink Automation triggers performUpkeep.

3. Chainlink VRF requests randomness.

4. A random winner is selected.

5. The winner receives the contract balance.

6. The raffle resets.

🧠 Security Features

• Custom errors (gas optimized)

• Strict state management

• Prevents entry during CALCULATING phase

• Validates upkeep before execution

• Ensures valid VRF request before fulfillment

📚 What This Project Demonstrates

• Smart contract architecture

• Chainlink VRF integration

• Automation integration

• Foundry testing framework

• Fuzz testing

• Deployment scripting

• Proper Git project structure

📜 License

MIT

👨‍💻 Author

Vedant Ghate