Splitzy

A local-first, AI-powered expense splitting app that works offline. Built with React Native and Expo.

Screenshots

Features

• 💡 Smart Scanning: AI-powered receipt scanning that automatically detects items
• ⚡ Local first: Split expenses anytime, anywhere - no internet required
• 👥 Group Friendly: Create unlimited groups for trips, roommates, or events
• 💸 Flexible Splitting: Split bills equally, by percentage, or custom amounts
• 🔄 Real-time Sync: Instantly sync expenses between devices using WebSocket

Tech Stack

• React Native with Expo
• SQLite for local storage
• Supabase for remote storage
• Google Generative AI for receipt scanning

Local development with Supabase

In development the app talks to a local Supabase stack: .env.development points SUPABASE_URL and SUPABASE_ANON_KEY at it. It needs Docker. The schema comes from supabase/migrations, so the local database always matches the versioned schema.

pnpm db:start     # start the local stack and apply the migrations
pnpm ios          # build and run the app as usual
pnpm db:login     # sign in as dev@splitzy.local in the booted iOS simulator

• pnpm db:login [email] [simulator] creates the user if needed, signs in with a magic link token through the admin API and opens the app with that session, so no email is sent. Pass a simulator name or UDID when several are booted. Signing in from the app's login screen does not work locally: auth emails go through the hosted SMTP settings in supabase/config.toml.
• pnpm db:offline / pnpm db:online stop and restart the local API gateway, which cuts every simulator off the backend at once. Local writes stay in the sync queue and are sent once the backend is back.
• pnpm db:reset recreates the local database from the migrations. pnpm db:stop stops the stack.
• Receipt scanning goes through SERVER_URL, which checks sessions against the hosted project, so it does not work with a local session.

Testing sync with two simulators

1. Boot two simulators and install the dev build on both, for example pnpm ios --device "iPhone 17" then pnpm ios --device "iPhone 17 Pro".
2. Sign in as two users: pnpm db:login alice@splitzy.local "iPhone 17" and pnpm db:login bob@splitzy.local "iPhone 17 Pro".
3. Create a group on the first one, then open the share link on the second, or run xcrun simctl openurl "iPhone 17 Pro" "splitzy-dev://protected/groups/<group id>/import".
4. Use pnpm db:offline, make changes on both, then pnpm db:online. Pull to refresh on the group screen to fetch what the other device sent while its realtime connection was down.