🎟️ Provably Fair Raffle Smart Contract

A decentralized, provably fair raffle system built on Ethereum using Chainlink VRF for secure randomness and Chainlink Automation for reliable execution.

🌟 Features

• Truly random winner selection using Chainlink VRF
• Automated raffle execution with Chainlink Automation
• Configurable for multiple networks (Mainnet, Sepolia, Anvil)
• Comprehensive testing suite
• Easy deployment and interaction scripts

🚀 Quick Start

Prerequisites

• Foundry
• Node.js
• Yarn

Installation

1. Clone the repository:

   git clone https://github.com/zeroaddresss/provably-fair-raffle.git
   cd provably-fair-raffle
   

2. Install dependencies:

   forge install
   yarn install
   

3. Set up environment variables:

   cp .env.example .env
   

   Edit .env and add your PRIVATE_KEY and other necessary variables.

Deployment

1. To deploy on a local Anvil chain:

   forge script script/DeployRaffle.s.sol --broadcast --rpc-url http://localhost:8545
   

2. To deploy on Sepolia testnet:

   forge script script/DeployRaffle.s.sol --broadcast --rpc-url $SEPOLIA_RPC_URL
   

📖 Detailed Documentation

Smart Contracts

• Raffle.sol: Main raffle contract
• HelperConfig.s.sol: Configuration helper for different networks
• Interactions.s.sol: Scripts for VRF subscription management

Key Functions

• enterRaffle(): Allow users to enter the raffle
• performUpkeep(): Trigger the raffle drawing (Chainlink Automation)
• fulfillRandomWords(): Callback for Chainlink VRF to provide randomness

Configuration

The HelperConfig.s.sol script provides configurations for:

• Mainnet Ethereum
• Sepolia Testnet
• Local Anvil chain

Adjust the parameters in this file to customize the raffle settings for each network.

🧪 Testing

Run the test suite:

forge test

For gas reports:

forge test --gas-report

🛠 Deployment and Interaction

1. Deploy the Raffle contract:

   forge script script/DeployRaffle.s.sol --broadcast --rpc-url $YOUR_RPC_URL
   

2. Interact with the deployed contract:

   cast send $RAFFLE_CONTRACT_ADDRESS "enterRaffle()" --value 0.1ether --rpc-url $YOUR_RPC_URL
   

🔗 External Dependencies

• Chainlink VRF: For verifiable randomness
• Chainlink Automation: For automated raffle execution

🙏 Acknowledgments

• Cyfrin for the amazing educational contents
• Chainlink for providing decentralized services
• Foundry for the amazing Ethereum development toolchain