Inventory & Billing Manager

Desktop inventory and billing app built with Tkinter for the UI and FastAPI for the local API layer.

What It Does

• Manage suppliers, products, customers, invoices, and invoice items
• Create billing invoices with automatic stock deduction
• Run as a single desktop app from run_gui.py
• Use MongoDB automatically when available
• Fall back to an in-memory demo database when MongoDB is not installed

Best Option For Your Teacher Demo

On another machine, especially a MacBook, you do not need to install MongoDB just to show the project.

The app now supports:

• INVENTORY_DB_MODE=auto: try MongoDB first, then fall back to in-memory demo data
• INVENTORY_DB_MODE=memory: always run with seeded demo data
• INVENTORY_DB_MODE=mongodb: require a real MongoDB connection

For a presentation, use memory mode so the app always opens with sample data.

macOS Setup

1. Install Python 3.11+.
2. Open Terminal in the project folder.
3. Create and activate a virtual environment.
4. Install dependencies.
5. Run the GUI.

Commands:

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
export INVENTORY_DB_MODE=memory
python run_gui.py

If your Mac Python does not include Tkinter, install Python from python.org and recreate the virtual environment. The app depends on Tkinter for the desktop window.

Windows Setup

python -m venv .venv
.\.venv\Scripts\Activate.ps1
pip install -r requirements.txt
$env:INVENTORY_DB_MODE="memory"
python run_gui.py

Optional MongoDB Mode

If you want to use a real database instead of demo mode, create a .env file from .env.example and set:

MONGODB_URI=mongodb://localhost:27017
MONGODB_DB=inventory_billing_db
INVENTORY_DB_MODE=mongodb
INVENTORY_DEMO_SEED=true

Then start the app normally:

python run_gui.py

Project Structure

.
├── app/
│   ├── config.py
│   ├── database.py
│   ├── gui.py
│   ├── main.py
│   ├── schemas.py
│   └── utils.py
├── run_gui.py
├── requirements.txt
└── README.md

Presentation Notes

• In demo mode, the app opens with sample suppliers, products, customers, invoices, and invoice items.
• The status bar shows whether you are using MongoDB or the in-memory demo backend.
• The GUI starts the local API automatically, so only python run_gui.py is needed.