PayMatrix

Name: PayMatrix
Author: Harshil Patel

Design · Full-Stack · AI · 2026

Group-expense platform with AI bill scanning (Gemini Vision), greedy debt simplification, native UPI deep-linking, and real-time sync.

Problem

Splitting group expenses is still a mess of screenshots, manual entry, and "who owes whom" chains. Existing apps make you type every line item by hand and settle debts through long chains of tiny transfers.

Approach

PayMatrix scans the physical bill instead — Gemini Vision reads the receipt, itemizes it, and assigns items to people. A greedy debt-simplification algorithm collapses the who-owes-whom graph into the minimum number of transfers, and each one deep-links straight into the payer's UPI app. Firebase keeps every member of the group in sync in real time.

Features

AI bill scanning — Point a camera at a receipt — Gemini Vision extracts merchant, line items, and totals into a structured split.
Debt simplification — A greedy settlement algorithm reduces N-person debt graphs to the fewest possible transactions.
Native UPI deep-linking — Every settlement opens directly in GPay/PhonePe/Paytm with amount and note pre-filled.
Real-time group sync — Expenses, edits, and settlements propagate to every member instantly via Firestore listeners.
Spending insights — Per-person and per-category breakdowns show where the group's money actually goes.

Outcome

Live in production and used for real group trips — the settle-up flow that used to take an evening of arithmetic now takes three taps.

Stack

React 19, Firebase, Tailwind, Gemini API

Links

Live site · GitHub

All projects · Harshil Patel

PayMatrix — Harshil Patel