Fund Me Smart Contract

A decentralized crowdfunding smart contract built with Solidity that allows users to fund the contract and only permits the owner to withdraw the funds. The contract includes price feed functionality using Chainlink oracles to convert ETH to USD.

Acknowledgments

This project was developed as part of the Cyfrin Updraft's Foundry Fundamentals course, an advanced smart contract development curriculum. The course provides comprehensive training in Foundry tooling and Solidity development best practices.

Features

• ETH to USD conversion using Chainlink Price Feeds
• Minimum funding amount requirement in USD
• Owner-only withdrawal
• Automated fund tracking per contributor
• Gas-optimized using immutable variables and custom errors
• Comprehensive test coverage

Tools & Technologies

• Solidity - Smart contract development
• Foundry - Development framework
• Chainlink - Price feed oracles

Prerequisites

• Git
• Foundry

Installation

1. Clone the repository

git clone https://github.com/your-username/fund-me
cd fund-me

2. Install dependencies

forge install

3. Build the project

forge build

Testing

Run the test suite:

forge test

For detailed gas reports:

forge test --gas-report

Deployment

1. Set up your environment variables:

cp .env.example .env

2. Add your private key and RPC URL to .env

3. Deploy to network:

forge script script/DeployFundMe.s.sol:DeployFundMe --rpc-url $RPC_URL --private-key $PRIVATE_KEY --broadcast

Contract Interaction

Funding

Send ETH to the contract (minimum 5 USD equivalent):

cast send <CONTRACT_ADDRESS> "fund()" --value 0.1ether --rpc-url $RPC_URL --private-key $PRIVATE_KEY

Withdrawal (Owner Only)

Withdraw all funds from the contract:

cast send <CONTRACT_ADDRESS> "withdraw()" --rpc-url $RPC_URL --private-key $PRIVATE_KEY

Contract Details

Key Functions

• fund(): Allows users to fund the contract with ETH
• withdraw(): Enables the owner to withdraw all funds
• getVersion(): Returns the price feed version
• getPrice(): Gets the latest ETH/USD price
• getConversion(): Converts ETH amount to USD
• getAddressToAmountFunded(): Returns amount funded by an address
• getFunder(): Returns funder at given index
• getOwner(): Returns contract owner address

Security Features

• Owner-only withdrawal using modifier
• Minimum funding amount check
• Chainlink price feed integration
• Withdrawal pattern implementation

License

This project is licensed under the MIT License.