SplitPay

SplitPay reimagines group expense settlement for the Web3 era. Just like Splitwise, you can track who paid for dinner, split Uber rides, and manage group expenses - but with a game-changing twist: our debt simplification algorithm reduces the number of payments needed by up to 75%. The Problem: In a typical friend group with multiple expenses, settling up requires numerous separate transfers. Four friends with 8 shared expenses might need 12 individual payments. Example scenario: Alice, Bob, Charlie, and Diana Expenses:

Hotel Room: $400 (paid by Alice) Group Dinner: $240 (paid by Bob) Uber Rides: $80 (paid by Charlie) Show Tickets: $360 (paid by Diana)

The Magic of Simplification Without SplitPay: 12 separate transactions would be needed as everyone pays everyone else for their share of each expense. With SplitPay: Only 3 transactions are needed:

Charlie → Alice: $110 Diana → Alice: $180 Bob → Diana: $20

Our Solution: SplitPay's algorithm simplifies this to just 3-4 optimized transfers. Then, with one click, everyone gets paid instantly using PayPal's PYUSD stablecoin. No more "I'll Venmo you later" or forgotten IOUs.

Key Features:

Add expenses and split them equally or custom amounts Visual debt simplification showing exactly how we reduce transfers One-click settlement with PYUSD on Ethereum Pay anyone using their ENS name (alice.eth instead of 0x...) Permanent receipts stored on Hedera for taxes/accounting

Perfect for hackathon teams, travel groups, shared housing, or any situation where multiple people share expenses.

We built SplitPay as a Next app withTypeScript, focusing on a smooth UX that rivals traditional fintech apps. The magic happens in our debt simplification algorithm - a min-cash-flow implementation that calculates net balances and uses greedy matching to minimize transfers. Technical Stack:

Frontend: React + Next + Tailwind CSS for a Splitwise-like interface Web3: Wagmi for wallet connections Smart Contract: Custom Splitter contract for batch settlements. Foundry and Solidity

Partner Technology Integration: PayPal (PYUSD): We integrated PYUSD as our settlement currency. Since it's an ERC-20 token on Ethereum, we could leverage standard Web3 tooling while providing users with a stable, regulated payment method. Our smart contract handles batch PYUSD transfers in a single transaction. ENS: Instead of copying long wallet addresses, users simply enter their friend's ENS name. We resolve these on-the-fly and display them throughout the app, making crypto payments as easy as Venmo. Hedera: Every settlement generates an immutable receipt stored on Hedera's network. We use Hedera's Topic Service for efficient storage of JSON receipts, which is inexpensive than storing on Ethereum while maintaining cryptographic proof.