Solo Developer · Jan 2025 — Mar 2025

Track spending. Zero effort.

Koin automatically detects your UPI and bank transactions the moment they happen — no manual entry, no sign-up required.

Case Study →

Built for: Indian smartphone users aged 22-35 who use UPI apps (GPay, PhonePe, Paytm) daily and want to understand their spending without the discipline overhead of manual tracking.

The Why

The Problem

You open your banking app to check how much you spent this month. You cannot tell — it is a wall of raw transactions with no categories, no totals, no context. You try a budgeting app, but it wants you to log every expense manually. You do it for three days, then forget.

The Solution

Koin hooks into your SMS inbox and payment app notifications to log transactions automatically the moment they happen. It categorizes them using Indian payment context — it knows that a Zomato charge is food, not other.

What it does

Key Features

Auto transaction detection

Koin reads your bank SMS and payment app notifications in real time, logging transactions the instant they occur — no copy-pasting required.

🧠

Smart categorization

A 7-tier AI pipeline figures out whether that Swiggy charge is food delivery, not just shopping — and it learns your corrections over time.

📊

Budget tracking

Set a daily, weekly, or monthly budget. Koin shows you exactly how much you have spent and how much is left — updated with every transaction.

📈

Analytics & insights

See 6-month spending trends, category breakdowns, and month-over-month comparisons. Koin surfaces anomalies and pattern shifts automatically.

🔒

Biometric security

Your financial data stays locked behind Face ID or fingerprint. The app locks automatically when you leave and unlocks with a glance.

☁️

Works offline, syncs silently

All data lives on your device first. Firebase sync happens in the background — so the app is always fast and works without a connection.

Technology

Built with

React NativeExpoTypeScriptReact NavigationMMKVFirebase FirestoreFirebase Authexpo-local-authenticationEAS BuildAndroid Native Modulesexpo-clipboardexpo-crypto

Results

Impact

7-tier
categorization pipeline
9+
Indian payment apps auto-detected
500+
merchant keywords mapped
3
transaction detection channels

Interested in working together?

This is one of many projects by Mudassir Mohammed. See the full portfolio or get in touch.

View Portfolio ↗Get in Touch →