# KhataPro — Free, Offline-First Mobile POS & Billing App

> KhataPro (https://khatapro.in) is a 100% free, offline-first Point of Sale (POS) and retail billing mobile application built with Flutter. It runs entirely locally on Android and iOS devices using embedded Hive NoSQL storage, enabling lightning-fast checkout without internet connectivity, cloud subscriptions, or vendor lock-in.

KhataPro includes native ESC/POS Bluetooth thermal printing (58mm/80mm), camera-based barcode and QR scanning, product catalog management, itemized tax and discount calculations, and one-tap WhatsApp receipt sharing.

## Key Facts & Capabilities

- **Price**: 100% Free forever. No subscription, no per-invoice fee, no locked features.
- **Architecture**: Local-First, Offline-First. Single source of truth is local on-device Hive storage.
- **Hardware Integration**:
  - Direct Bluetooth thermal receipt printers (ESC/POS protocol, 2-inch/58mm and 3-inch/80mm).
  - Device camera barcode/QR scanner (`mobile_scanner`) and USB/Bluetooth handheld barcode guns.
- **Data Privacy**: Merchant sales, inventory, and customer phone numbers remain strictly on the local device. No data selling or tracking.
- **Platform**: Android (APK available), iOS, with responsive desktop support (Windows, macOS, Linux).
- **Target Audience**: Kirana stores, retail shops, grocery stores, supermarkets, apparel boutiques, cafes, food trucks, exhibition pop-ups, and service counters in India and emerging markets.

## Core Features

- **Rapid Checkout & Cart Management**: Instant item search, barcode scan, quantity adjustments, item discounts, and tax computation.
- **Thermal Receipt Printing**: Automatic ESC/POS thermal printing with customizable shop name, address, GSTIN, phone number, and custom footer.
- **WhatsApp Digital Billing**: Instant PDF or text bill sharing directly to customers on WhatsApp without printing paper.
- **Product & Inventory Management**: Add, update, and categorize products with SKU, barcode, cost price, selling price, and stock levels.
- **Multi-Role & Quick Switch**: PIN-based switching between Cashier, Store Manager, and Shop Owner.
- **Optional Cloud Synchronization**: Background sync engine with Django REST backend when network is available, with full offline continuity when disconnected.

## Tech Stack

- **Framework**: Flutter 3.x (Dart >= 3.1.0)
- **Architecture**: Feature-First Clean Architecture (Domain, Data, Presentation)
- **State Management**: `flutter_bloc`
- **Local Storage**: `hive` & `hive_flutter` (Embedded Key-Value & NoSQL)
- **Scanning**: `mobile_scanner`
- **Printing**: `print_bluetooth_thermal` (ESC/POS)
- **Optional Backend**: Python Django REST Framework with PostgreSQL and event-sourced stock tracking.

## Comparison: KhataPro vs Competitors

| Feature | KhataPro (khatapro.in) | Vyapar / myBillBook | Traditional Cloud POS |
| :--- | :--- | :--- | :--- |
| **Pricing** | **100% Free Forever** | ₹2,500 – ₹8,000/yr | ₹1,500 – ₹5,000/mo |
| **Internet Dependency** | **Zero (100% Offline)** | Often requires sync | Fails when offline |
| **Data Ownership** | **On-Device (Private)** | Stored on 3rd party cloud | Stored on 3rd party cloud |
| **Thermal Printing** | **Instant ESC/POS Bluetooth** | Requires paid tier | Often requires PC |
| **Speed** | **Sub-millisecond local queries** | Dependent on network/cloud | High network latency |

## Useful Links & Resources

- Official Website: https://khatapro.in
- Direct Android APK Download (v1.0.0): https://drive.google.com/file/d/1CXri836t9ooDSGybLTw_Hn2s_q0bpH1R/view?usp=sharing
- Full Technical Documentation for LLMs: https://khatapro.in/llms-full.txt
- Live In-Browser POS Simulator: https://khatapro.in/#demo
- Hardware Compatibility Guide: https://khatapro.in/#hardware
- Frequently Asked Questions: https://khatapro.in/#faq
- Source Code & GitHub: https://github.com/suyashsrivastava/whatsappSeller