Khata – Offline Ledger & Billing Android App

Khata is a production-ready, offline-first Android application designed to manage customers, items, and financial transactions efficiently.
It works completely offline, supports billing, reports, and data export/import, and is built using Clean Architecture with Room Database.

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✨ Features

👥 Customer Management

• Create, update, delete customers
• View complete transaction history per customer
• Track balances (credit / debit)
• Customer-wise reports and summaries

📦 Item Management

• Add and manage items/products
• Item-wise transaction tracking
• Pricing and usage history

💸 Transaction Handling

• Record credit & debit transactions
• Offline transaction processing
• Full transaction history
• Edit, delete, and manage past records

🧾 Billing & Invoices

• Generate professional bills
• Print bills directly
• Share bills via PDF
• Reprint past invoices

📄 PDF & Reports

• Generate transaction PDFs
• Customer and item history reports
• Share or print reports anytime

📊 Data Export & Restore

• Export complete database to Excel
• Restore data from Excel backup
• Safe offline backup & recovery

🌙 UI & UX

• Light Theme & Dark Theme
• Clean and minimal UI
• Optimized for daily business use

🗓 Nepali Date Support

• Uses custom Nepali Date library
• Accurate local date handling for transactions and reports

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🧱 Architecture

The app follows Clean Architecture, ensuring scalability, testability, and long-term maintainability.

presentation/ domain/ data/

yaml Copy code

Key Principles:

• Separation of concerns
• Business logic independent of UI
• Easily extensible and maintainable

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🛠 Tech Stack

• Language: Kotlin
• Architecture: Clean Architecture (MVVM-based)
• Database: Room (SQLite)
• Offline First: Yes
• PDF Generation: Native Android APIs
• Export Format: Excel
• Date System: Custom Nepali Date Library
• UI: Material Design
• Themes: Light & Dark

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📦 Core Modules

• Customers
• Items
• Transactions
• Billing & Invoices
• Reports & History
• Backup & Restore

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🔐 Data Safety

• Fully offline
• No external server dependency
• Local encrypted Room database (if enabled)
• Manual backup & restore support

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🚀 Production Ready

• Optimized for real-world usage
• Clean codebase
• Scalable architecture
• Ready for Play Store deployment
• Tested with real transaction flows

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👨‍💻 Author

Madan Raj Upadhyay
AI and Android Developer

⭐ Support

If you find this project useful, consider giving it a ⭐ on GitHub!