DeFi Staking Pool

A simple time-based staking contract built with Solidity and Foundry. Users can stake ERC20 tokens and earn rewards proportional to their stake over a defined period.

Overview

This project includes two main contracts:

• RewardToken: A standard ERC20 token with mint/burn functionality
• StakingPool: A staking contract that distributes rewards to stakers over time

The staking pool implements the Synthetix staking rewards model, which uses a reward-per-token calculation to ensure fair distribution based on both stake amount and duration. Rewards are distributed continuously over a 30-day period (configurable).

Setup

Install dependencies:

forge install

Copy the example environment file and add your private key:

cp .example.env .env

Testing

Run tests:

forge test

For gas reporting:

forge test -vv

Run specific tests:

forge test --match-contract StakingPoolTest
forge test --match-test testStake

Deployment

Deploy to Sepolia testnet:

forge script script/Deploy.s.sol:DeployScript --rpc-url https://ethereum-sepolia-rpc.publicnode.com --broadcast -vvvv

The deploy script will:

1. Deploy the RewardToken with an initial supply
2. Deploy the StakingPool contract
3. Log both contract addresses

Contract Architecture

RewardToken

Standard ERC20 with:

• Owner-controlled minting
• Public burn function
• Initial supply minted to deployer

StakingPool

Features:

• Stake tokens to earn rewards
• Withdraw staked tokens at any time
• Claim accumulated rewards
• Emergency withdraw (forfeit rewards)
• Owner can add rewards to extend/refresh the reward period

The pool tracks rewardPerToken which increases based on time elapsed and total staked amount. Each user's rewards are calculated by multiplying their stake by the difference between current and their last recorded rewardPerToken. This allows for efficient reward calculation without iterating through all stakers.

Usage Example

// Stake tokens
token.approve(address(stakingPool), amount);
stakingPool.stake(amount);

// Check earned rewards
uint256 earned = stakingPool.earned(userAddress);

// Claim rewards
stakingPool.getReward();

// Withdraw stake
stakingPool.withdraw(amount);

Security

• Uses OpenZeppelin's ReentrancyGuard for state-changing functions
• SafeERC20 for all token transfers
• Owner-only functions for privileged operations
• Emergency withdraw function for users in case of issues

License

MIT