A powerful GST billing software for Indian businesses with inventory management, invoice generation, and offline-first PWA support.

Supports:

• GST invoicing (CGST, SGST, IGST)
• Inventory & stock management
• Offline billing system
• Small business / shop billing use-case

A high-performance, mobile-first Progressive Web Application (PWA) built for robust, offline-capable GST billing and inventory management. This application has been developed to adhere strictly to Indian taxation requirements (CGST, SGST, IGST calculations) with fully localized numerical formatting.

• Progressive Web App (PWA): Installable on iOS and Android devices directly from the browser. Supports offline caching for core modules.
• Inventory Management: Real-time stock tracking, expiration alerts, and comprehensive batch management (FIFO/LIFO ready).
• Billing Engine: Automated, error-free GST calculations, smart autocomplete for returning products, and instant dynamic total generation.
• Document Generation: Print-ready A4 formatting for generating hard-copy or PDF invoices.
• Reporting & Dashboard: Visual representation of monthly sales velocities and key performance indicators.
• Data Governance: Zero cloud dependency. 100% data ownership with built-in export (CSV) and full SQLite database backup/restore mechanics.

• Frontend: React 18 (TypeScript), Vite, Tailwind CSS, Recharts, Zustand, Date-FNS.
• Backend: FastAPI (Python), SQLAlchemy, SQLite, Pydantic, PassLib.
• Deployment: Docker, Nginx.

Ensure you have Python 3.11+ installed.

cd backend
python -m venv venv
source venv/bin/activate  # On Windows use `venv\Scripts\activate`
pip install -r requirements.txt

Run the backend development server:

uvicorn main:app --reload --port 8000

The API will be available at http://localhost:8000.

Ensure you have Node.js 18+ installed.

cd frontend
npm install --legacy-peer-deps

Run the frontend development server:

npm run dev

The UI will be available at http://localhost:5173.

This application comes with a production-ready Docker Compose configuration.

1. Ensure Docker and Docker Compose are installed.
2. Copy the .env.example file to .env:

   cp .env.example .env

3. Update the .env file with a secure, random SECRET_KEY.
4. Build and start the containers:

   docker-compose up --build -d

The application will now be running at http://localhost:80 (Frontend) and http://localhost:8000 (Backend API).

• Auth: JWT-based authentication storing tokens locally.
• Database: SQLite database stored locally. In a Docker environment, it uses a persistent Docker Volume db_data to ensure your data survives container restarts.
• PWA Config: Utilizes vite-plugin-pwa alongside Workbox to aggressively cache CSS, JS, and essential API endpoints for partial offline resilience.

• Strict Formatting: Rupee (₹) formatting with exactly 2 decimal places.
• No Third-Party APIs: This system is completely self-contained. It relies on zero external APIs to ensure total data sovereignty and operation in low-connectivity zones.