Spoločné výdavky — Shared Expenses

Inspiration

Every group trip ends the same way — someone paid for the hotel, someone for gas, and by Sunday nobody knows who owes what. We wanted to fix that inside the app people already trust with their money: their bank.

What it does

Spoločné výdavky lets you create groups — family, roommates, friends on a trip — add shared expenses, and instantly see who owes whom. Balances update in real time so everyone always knows where they stand. One tap to settle a debt. You can also scan a paper receipt with your camera: Gemini AI reads the items, you assign each one to the right person, and the split is sent to the group instantly.

How we built it

Next.js, TypeScript, Tailwind CSS and shadcn/ui for the frontend — pixel-matched to the Tatra Banka design system. MongoDB Atlas stores all groups and expenses. Receipt OCR runs through Google Gemini. Deployed on DigitalOcean App Platform.

Accomplishments that we're proud of

The UI feels like a real Tatra Banka feature. We shipped a working MongoDB backend, AI-powered receipt scanning, and group subscriptions vault

What's next for hack-ke-lama

Direct in-app settlement via Tatra Banka PIS (Payment Initiation) — the OAuth scaffolding is already in place
Voice debt summary via ElevenLabs — TABI reads out your balances out loud
Spending limits per category with push notifications before you overspend
Recurring expense templates — rent splits that auto-generate every month