A social fitness challenge app where friends commit to running goals, stake ETH or USDC, prove they completed the run, and the pot is automatically distributed to winners.

Built on Base for the MBC Hackathon • Base Track + Circle USDC Bounty

1. Overview
2. Problem & Solution
3. Circle USDC Integration
4. Features
5. Tech Stack
6. Architecture
7. Quick Start
   • Local Development
   • Base Sepolia Deployment
8. Smart Contracts
9. User Flows
10. Deployed Contract Addresses
11. Resources
12. License

Stride is a decentralized fitness accountability platform that leverages blockchain-based financial incentives to help users achieve their fitness goals. Users create or join challenges, stake cryptocurrency (ETH or USDC), and winners who complete their goals split the pot.

• Low Fees: Transaction costs are minimal, making small stakes viable
• Fast Finality: Quick confirmation times for seamless UX
• EVM Compatible: Full Solidity support with familiar tooling
• Coinbase Ecosystem: Integration with Coinbase Smart Wallet for easy onboarding

• 80% of New Year's resolutions fail by February
• People struggle with fitness accountability
• Traditional fitness apps lack real skin-in-the-game incentives
• Cross-border participation is difficult with fiat currencies

Stride creates social accountability with financial stakes:

• Put real money on the line with friends
• Complete your fitness goal or lose your stake
• Winners are rewarded with a share of the losers' stakes
• Global participation via USDC (dollar-denominated)

This project integrates Circle's USDC stablecoin for fitness challenge staking, demonstrating a real-world payment use case on Base.

// Uses Circle USDC (6 decimals) for all staking
IERC20 public immutable usdc;

// Create challenge with USDC stake
function createChallenge(
    uint256 stakeAmount,    // USDC amount (6 decimals)
    uint256 duration,
    string calldata description,
    uint256 groupId
) external returns (uint256 challengeId)

• Circle Faucet: https://faucet.circle.com/ (Base Sepolia)
• USDC Address (Base Sepolia): 0x036CbD53842c5426634e7929541eC2318f3dCF7e

• Create Challenges - Set custom fitness goals with descriptions
• Dual Currency - Stake ETH or USDC (Circle integration)
• Group Challenges - Create and join groups with friends
• Leaderboards - Track group member performance and win streaks
• Proof of Completion - Mark runs as complete on-chain
• Auto Settlement - Smart contract distributes prizes automatically
• NFT Badges - On-chain SVG achievement badges
• Early Settlement - Vote to end challenges early (consensus)
• Refund Voting - Democratic cancellation with full refunds

• Next.js 15 with TypeScript & App Router
• Tailwind CSS for modern styling
• wagmi v2 + viem for Web3 interactions
• Coinbase Wallet integration (Smart Wallet ready)

• Solidity 0.8.24 with OpenZeppelin
• Hardhat for development, testing, and deployment
• Circle USDC integration (ERC20)
• On-chain SVG NFT generation

• Base Sepolia (Testnet)
• Hardhat (Local development)

┌─────────────────────────────────────────────────────────────────┐
│                         Frontend (Next.js)                       │
├─────────────────────────────────────────────────────────────────┤
│  wagmi hooks │ USDC Components │ Challenge UI │ Group UI │ NFTs │
└───────────────────────────┬─────────────────────────────────────┘
                            │
                    ┌───────▼───────┐
                    │  wagmi/viem   │
                    └───────┬───────┘
                            │
┌───────────────────────────▼─────────────────────────────────────┐
│                     Base (L2 Ethereum)                           │
├─────────────────────────────────────────────────────────────────┤
│                                                                  │
│  ┌──────────────────────┐  ┌───────────────────────────────┐    │
│  │ StrideChallengeManager│  │ StrideUSDCChallengeManager    │    │
│  │      (ETH stakes)     │  │   (Circle USDC stakes)        │    │
│  └──────────┬───────────┘  └──────────────┬────────────────┘    │
│             │                              │                     │
│             │         ┌────────────────────┼───────────────┐     │
│             └────────►│   StrideGroups     │◄──────────────┘     │
│                       │ (Leaderboards &    │                     │
│                       │  Group Management) │                     │
│                       └────────────────────┘                     │
│                                                                  │
│  ┌────────────────────┐   ┌──────────────────────────────────┐  │
│  │   SimpleBadgeNFT   │   │  Circle USDC Token (ERC20)       │  │
│  │  (On-chain SVG)    │   │  0x036CbD53842c5426634e7929...   │  │
│  └────────────────────┘   └──────────────────────────────────┘  │
│                                                                  │
└─────────────────────────────────────────────────────────────────┘

• Node.js 18+
• A wallet with Base Sepolia ETH (Faucet)
• Testnet USDC from Circle Faucet

# Clone the repository
git clone https://github.com/your-username/stride.git
cd stride

# Install frontend dependencies
npm install

# Install contract dependencies
cd contracts && npm install && cd ..

cd contracts

# Start Hardhat node (keep this running)
npx hardhat node

cd contracts

# Deploy all contracts including MockUSDC
npx hardhat run scripts/deployAll.ts --network localhost

You'll see output like:

📋 Contract Addresses:
┌────────────────────────────────────────────────────────────┐
│ StrideChallengeManager (ETH):  0x3Aa5ebB10DC797CAC828524...│
│ StrideGroups:                  0xc6e7DF5E7b4f2A278906862...│
│ SimpleBadgeNFT:                0x4ed7c70F96B99c776995fB6...│
│ USDC Token:                    0xa85233C63b9Ee964Add6F2c...│
│ StrideUSDCChallengeManager:    0x4A679253410272dd5232B3F...│
└────────────────────────────────────────────────────────────┘

Create .env.local in the project root:

# Enable local development mode
NEXT_PUBLIC_LOCAL_DEV=true

npm run dev

Open http://localhost:3000

1. Add Hardhat Network to MetaMask:

   • Network Name: Hardhat
   • RPC URL: http://127.0.0.1:8545
   • Chain ID: 31337
   • Currency Symbol: ETH

2. Import a test account from Hardhat (use one of the private keys shown when starting the node)

Create contracts/.env:

PRIVATE_KEY=your_wallet_private_key
BASE_SEPOLIA_RPC=https://sepolia.base.org

cd contracts

# Deploy all contracts
npx hardhat run scripts/deployAll.ts --network baseSepolia

Update .env.local:

# Remove local dev flag for production
# NEXT_PUBLIC_LOCAL_DEV=true

# Contract addresses from deployment
NEXT_PUBLIC_CONTRACT_ADDRESS=0x...
NEXT_PUBLIC_GROUPS_CONTRACT_ADDRESS=0x...
NEXT_PUBLIC_NFT_CONTRACT_ADDRESS=0x...
NEXT_PUBLIC_USDC_CONTRACT_ADDRESS=0x...
NEXT_PUBLIC_USDC_ADDRESS=0x036CbD53842c5426634e7929541eC2318f3dCF7e

function createChallenge(
    uint256 stakeAmount,
    uint256 duration,
    string calldata description,
    uint256 groupId
) external payable returns (uint256 challengeId)

function joinChallenge(uint256 challengeId) external payable

function markCompleted(uint256 challengeId) external

function settleChallenge(uint256 challengeId) external

1. User enters stake amount in the UI
2. Frontend checks current USDC allowance
3. If insufficient, prompts for approval transaction
4. After approval, user can stake USDC
5. Contract uses SafeERC20.safeTransferFrom() for security

1. Connect wallet
2. Navigate to a group or create one
3. Click "Create Challenge"
4. Select USDC as currency
5. Approve USDC spending (one-time or per-challenge)
6. Set description, duration, and stake amount
7. Submit transaction

1. Browse available challenges
2. Click "Join Challenge"
3. Approve USDC if needed
4. Confirm transaction

1. Complete your fitness goal IRL
2. Click "I Finished My Run!"
3. Wait for challenge deadline
4. Anyone can click "Settle" to distribute prizes

Run npx hardhat run scripts/deployAll.ts --network localhost to get fresh addresses.

• Base Docs: https://docs.base.org/
• Base Sepolia Faucet: https://www.alchemy.com/faucets/base-sepolia
• BaseScan: https://sepolia.basescan.org/

• Developer Docs: https://developers.circle.com/
• USDC on Base: https://www.circle.com/en/usdc-multichain/base
• Testnet Faucet: https://faucet.circle.com/
• Bridge Kit: https://developers.circle.com/w3s/bridge-kit

MIT

Built for MBC Hackathon 2025 • Powered by Circle USDC • Built on Base