#Decentralized Raffle Smart Contract

This is a decentralized raffle system built on the Ethereum blockchain. Participants can enter the raffle by paying an entrance fee in ETH, and a winner is selected automatically using Chainlink's Verifiable Random Function (VRF). The contract ensures fairness, transparency, and automation through smart contract logic.

🌟 ##Features

Entrance Fee : Users must pay a fixed entrance fee in ETH to participate. Random Winner Selection : Uses Chainlink VRF to generate a provably random number for selecting the winner. Automated Execution : Operates on a time-based interval; the winner is picked automatically when the timer expires. Transparent and Trustless : Fully decentralized and verifiable on-chain.

🛠 ##Technologies Used

Solidity : For writing the smart contract. Foundry : For testing, deployment, and scripting. Chainlink VRF : For secure and verifiable random number generation. Sepolia Testnet : Deployed and tested on the Sepolia Ethereum testnet.

🚀 ##Quick Start

1. Prerequisites

Install Foundry . Set up an Ethereum wallet with Sepolia testnet ETH (use a faucet like Sepolia Faucet ). Obtain a Chainlink VRF subscription ID and fund it with LINK tokens on Sepolia.

2. Clone the Repository

git clone https://github.com/Avinesh-Git/foundry-smartcontract-raffle
cd smart-contract-raffle

3. Set Up Environment Variables Create a .env file in the root directory and add the following:

SEPOLIA_RPC_URL=https://****/YOUR_INFURA_PROJECT_ID
PRIVATE_KEY=YOUR_PRIVATE_KEY
ETHERSCAN_API_KEY=YOUR_ETHERSCAN_API_KEY

4. Install Dependencies Install any required dependencies using Foundry:

forge install

5. Run Tests Run the integration tests to ensure everything works as expected:

forge test

6. Deploy to Sepolia Deploy the contract to the Sepolia testnet:

make deploy-sepolia

After deployment, verify the contract on Etherscan using the --verify flag.

📝 ##How It Works

Participants Enter : Users send ETH to the contract to enter the raffle. Timer Starts : The raffle runs for a predefined interval (e.g., 30 seconds). Winner Selected : Once the timer expires, Chainlink VRF generates a random number to select the winner. Prize Distributed : The winner receives the accumulated ETH from all participants.

🔧 ##Scripts and Commands

Test : Run tests using Foundry.

forge test

Deploy : Deploy the contract to Sepolia.

make deploy-sepolia

Interact : Use cast or Etherscan to interact with the deployed contract.

📈 ##Gas Optimization Gas usage has been optimized where possible:

Events are used instead of storing unnecessary data on-chain. Loops and excessive storage writes have been minimized.

🛡 ##Security The contract has been tested using Foundry.

📜 ##License This project is licensed under the MIT License.