A simple, clean expense tracking app with Rule-based expense parsing. Built with Svelte (Vite) on the frontend and Express + Prisma (SQLite) on the backend.

• Frontend: Svelte + Vite + TypeScript, Tailwind CSS
• Backend: Node.js (Express + TypeScript), Prisma ORM, SQLite
• Auth: JWT (username + password)
• Rule-based Parsing: Enhanced rule-based parser for natural language expense parsing (fully local, no external APIs)

• Rule-based expense entry parsing: "Add two flights at 1500 each to my Japan trip" → parsed into category/type/qty/price/total
• Manual expense entry form
• Trips and participants (shared expenses)
• Split expenses among members (default equal split)
• Authentication (register/login)

• Node.js 20.19+ (or 22.12+ / 24+). Recommended: Node 22 LTS
• npm 10+

1. Clone and install dependencies

cd divvyup
cd backend && npm i && cd ..
cd frontend && npm i && cd ..

2. Configure environment

• Backend backend/.env (already created during scaffolding). If missing, create it:

DATABASE_URL="file:./dev.db"
JWT_SECRET="dev_secret_change_me"
PORT=4000

• Frontend frontend/.env:

VITE_API_BASE="http://localhost:4000"

3. Initialize database

cd backend
npx prisma generate
npx prisma migrate dev --name init

4. Run the apps (two terminals)

• Backend

cd backend
npm run dev

API: http://localhost:4000

• Frontend

cd frontend
npm run dev

UI: http://localhost:5173

divvyup/
  backend/
    prisma/
      schema.prisma
      migrations/
      dev.db                # SQLite DB (ignored by git)
    src/
      routes/               # auth, trips, expenses, ai
      middleware/
      server.ts
      prisma.ts
      config.ts
    package.json
  frontend/
    src/
      views/                # Login, Register, Dashboard, Trip
      lib/                  # api.ts, auth.ts
      App.svelte
      app.css
    index.html
    package.json

• POST /auth/register { username, password } → { token, user }
• POST /auth/login { username, password } → { token, user }
• GET /trips (auth)
• POST /trips { name } (auth)
• POST /trips/:tripId/members { username } (auth, owner)
• GET /trips/:tripId/expenses (auth)
• POST /expenses { tripId, description, amount, category?, expenseType?, quantity?, unitPrice?, incurredAt?, splits? } (auth)
• POST /ai/parse { input } (auth)

Notes

• Amounts are stored as integer cents in the DB (e.g., $12.34 → 1234).
• When splits is omitted, expenses default to equal split among members (or the creator if no members).

The app uses an enhanced rule-based parser that runs entirely locally to extract expense information from natural language input. No external APIs or internet connection required.

What it extracts:

• tripName: Destination or trip name ("Japan trip", "Paris vacation")
• expenseType: Category ("Flight", "Hotel", "Meal", "Transport", "Entertainment", "Shopping", "Other")
• quantity: Number of items (2 flights, 3 nights, 5 tickets)
• unitPrice: Price per item (150 each, 80 per night)
• amount: Total amount (calculated or explicitly stated)

Supported input patterns:

• "Flight to Tokyo for $450"
• "Hotel in Paris for 3 nights at 120 EUR each"
• "Two train tickets at 25 each for my Japan trip"
• "Museum tickets for 5 people at 15 each"
• "€200 for shopping in Rome trip"
• "My vacation in Bali - hotel cost 150 per night for 7 nights"

Example input

I want to register an expense for my trip to Japan. I just bought two flights at 1500 each and need you to add that to my Japan trip.

Expected extraction

• tripName: "Japan trip"
• expenseType: "Flights"
• quantity: 2
• unitPrice: 1500
• amount: 3000

• Use a strong JWT_SECRET in production.
• Commit Prisma migrations; do not commit the SQLite database file.
• The frontend uses hash-based routing; URLs start with #/.

MIT