SpendWise - Smart Expense Tracker

A privacy-first expense tracking app for India with automatic transaction capture from UPI apps, bank notifications, and receipt scanning.

The Problem 💭

Every month, people struggle to track where their money goes. Transactions are scattered across UPI apps (Google Pay, PhonePe, PayTM), credit/debit cards, digital wallets, and subscriptions. There's no single, simple view of everyday expenses in plain language.

That's why I built SpendWise — to solve this exact problem.

How It Was Built 🔨

Phase 1: Understanding the Problem

I started by researching why expense tracking is so hard. The main issues I identified:

• Fragmentation — Transactions live across 10+ apps
• Friction — Manual entry takes 30+ seconds per transaction
• Invisibility — One-tap payments make spending feel "invisible"
• Confusion — Bank statements show cryptic codes, not real merchant names

Phase 2: Architecture Design

I chose a privacy-first approach — all data stays on the device. No cloud, no accounts, no sync.

Transaction Happens
        ↓
   ┌────┴─────┐
   │          │
Notification  Photo Capture
Listener     (Receipt OCR)
   │          │
   └────┬─────┘
        ↓
   Data Fusion Engine
   (Combine sources)
        ↓
   Auto-Categorization
        ↓
   User Confirmation
        ↓
   Store & Learn

Phase 3: Technology Selection

After evaluating options, I selected:

• Flutter — Cross-platform, fast development
• Riverpod — Modern state management
• SQLite — Reliable local storage
• Google ML Kit — Free, on-device OCR
• fl_chart — Beautiful, customizable charts

Phase 4: Feature Implementation

Notification Capture (The "Magic" Feature)

Built a service to listen to Android notifications from bank apps. Used regex patterns to extract:

• Transaction amount
• Merchant name
• Date/time
• Bank name

Supported apps: Google Pay, PhonePe, PayTM, HDFC, SBI, ICICI, Axis, and 15+ more.

Receipt Scanning (OCR)

Integrated Google ML Kit for on-device text recognition. Built custom parsers to extract:

• Total amount (even from messy receipts)
• Merchant name
• Date
• Line items

Smart Categorization

Created 50+ keyword rules that auto-categorize transactions:

• "swiggy", "zomato", "dominos" → Food & Dining
• "uber", "ola", "metro" → Transport
• "amazon", "flipkart" → Shopping

The system learns from user corrections — if you change a category, it remembers.

Dashboard & Visualization

Built an intuitive dashboard showing:

• Monthly spending total
• Category breakdown (pie chart)
• Recent transactions
• Month-over-month comparison

Phase 5: Testing & Polish

• 10 unit tests for notification parsing
• Manual testing across different Android versions
• UI polish for Material Design 3
• Dark mode support

Features

• 📱 Automatic Transaction Capture - Captures transactions from bank apps and UPI notifications
• 🧾 Receipt Scanning - Scan receipts with OCR to auto-extract amounts
• 🏷️ Smart Categorization - Automatically categorizes expenses
• 📊 Visual Insights - Beautiful charts showing spending by category
• 🔒 Privacy First - All data stored locally on your device
• 🌙 Dark Mode - Easy on the eyes theme support

Supported Apps

UPI Apps

• Google Pay
• PhonePe
• PayTM
• Amazon Pay
• BHIM UPI

Banks

• SBI, HDFC, ICICI, Axis, Kotak, IDFC, and more

Tech Stack

Layer	Technology	Why
Framework	Flutter 3.24	Fast, cross-platform
Language	Dart	Flutter's native language
State	Riverpod	Type-safe, testable
Database	SQLite	Reliable, local-only
OCR	Google ML Kit	Free, on-device
Charts	fl_chart	Beautiful visualizations
Architecture	Clean Architecture	Scalable, maintainable

Getting Started

Prerequisites

• Flutter SDK 3.x
• Android Studio / Android SDK
• Android device or emulator (API 24+)

Installation

1. Clone the repository

git clone https://github.com/badalsharma9929/spendwise.git
cd spendwise

2. Get dependencies

flutter pub get

3. Run the app

flutter run

Building APK

# Debug build
flutter build apk --debug

# Release build
flutter build apk --release

Project Structure

lib/
├── core/              # Constants, theme, utilities
├── data/              # Database, models, repositories, services
├── domain/            # Entities, repository interfaces
└── presentation/      # Pages, widgets, providers, router

Future Enhancements 🚀

• iOS support
• Cloud backup (optional, with user consent)
• Budget alerts
• Recurring transaction detection
• Export to CSV/PDF
• Multi-currency support
• Investment tracking

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License.

Author

Badal Sharma

• GitHub: @badalsharam9929

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