Fintech ~10 hours to build

Smart Expense Splitter

Group expenses without the awkward conversations.

The Problem

Every group trip, every dinner with friends, every shared house ends the same way: someone Venmo-requesting, others forgetting who paid what, and awkward "you still owe me $23" conversations weeks later. Splitwise exists but feels dated and bloated. People want something simpler.

The Solution

A clean, modern expense splitter that creates a group, logs expenses, and calculates the minimum number of payments needed to settle up. Integrates with Venmo/PayPal for one-tap settlement. Works great for trips, roommates, and regular dinner groups.

How it works:

1

Create group

Invite friends via link

2

Log expenses

Who paid, who's involved

3

Settle up

Optimized payments via Venmo

Market Research

Expense splitting is evergreen. Splitwise has 50M+ downloads but hasn't innovated in years. Younger users want modern design and faster settlement options.

Splitwise valued at $1B+ with premium features at $5/month
70% of millennials regularly split expenses with friends
Travel spending rebounding—group trips need expense tracking

AI Prompts to Build This

Copy and paste these into Claude, Cursor, or your favorite AI tool.

1. Project Setup

Create a Next.js PWA for an Expense Splitter app. Features: - Landing page with "Start a Group" CTA - Create group: name, invite link generation - Group dashboard: members, expenses list, balance summary - Add expense modal: amount, description, who paid, split type (equal/exact/percentage) - Each member sees their balance (owed/owing) Use Supabase auth (magic link for easy onboarding) and database. Make it installable as PWA for mobile.

2. Core Feature

Implement the settlement optimization algorithm: 1. Calculate net balance for each person (total paid - total owed) 2. People with positive balance are owed money; negative balance owe money 3. Implement minimum transaction algorithm: - Sort creditors and debtors - Match largest debtor with largest creditor - Settle minimum of both amounts - Repeat until all settled 4. Display settlement plan: "Alice pays Bob $50" etc. This minimizes total number of transactions needed.

3. Payment Integration

Add payment links for settlement: - Generate Venmo deep links: venmo://paycharge?txn=pay&recipients={username}&amount={amount}¬e={description} - Generate PayPal.me links: paypal.me/{username}/{amount} - Add "Mark as Paid" button to manually record settlements - Send push notification when someone marks payment complete - Keep history of all settlements Allow users to save their Venmo/PayPal username in settings.