FastAPI E-Commerce API

A robust and feature-rich RESTful API for e-commerce product management built with FastAPI, featuring advanced data validation, filtering capabilities, and an interactive Streamlit admin dashboard.

🚀 Features

Backend API (FastAPI)

• CRUD Operations: Complete product management (Create, Read, Update, Delete)
• Advanced Filtering: Filter products by name, category, price, with sorting and pagination
• Data Validation: Robust Pydantic models with custom validators
• Business Logic Validation:
  • SKU format validation
  • Stock and availability rules
  • Seller email domain restrictions
  • Rating and discount validation
• Computed Fields: Automatic calculation of final price and product volume
• HTTP Middleware: Request/response lifecycle logging
• Dependency Injection: Clean architecture with dependency management
• Environment Variables: Configuration via .env file

Frontend Dashboard (Streamlit)

• Interactive UI: Beautiful admin dashboard for product management
• Product Catalog: Browse, search, and filter products
• Add Products: User-friendly form to add new products
• Update/Delete: Manage existing products with ease
• Real-time API Integration: Direct communication with FastAPI backend

Data Model Features

• UUID-based product identification
• SKU validation with custom format requirements
• Multi-dimensional product attributes (dimensions, ratings, tags)
• Seller information with email domain validation
• Image URL support
• Timestamp tracking (created_at)

📋 Prerequisites

• Python 3.8 or higher
• pip (Python package manager)

🛠️ Installation

1. Clone the repository

   git clone <your-repository-url>
   cd fastapi_ecomerce

2. Create a virtual environment

   python -m venv venv

3. Activate the virtual environment

   • Windows:

     venv\Scripts\activate

   • macOS/Linux:

     source venv/bin/activate

4. Install dependencies

   pip install -r requirements.txt
   pip install streamlit  # For the frontend dashboard

5. Set up environment variables

   Create a .env file in the app/ directory:

   base_url=./app/data/products.json

6. Create the data directory

   mkdir -p app/data

7. Initialize the products database

   Create an empty products.json file:

   echo [] > app/data/products.json

🚀 Running the Application

Start the FastAPI Backend

uvicorn app.mainn:app --reload

The API will be available at: http://127.0.0.1:8000

API Documentation (auto-generated by FastAPI):

• Swagger UI: http://127.0.0.1:8000/docs
• ReDoc: http://127.0.0.1:8000/redoc

Start the Streamlit Frontend

In a new terminal (with the backend running):

streamlit run streamlit_app.py

The dashboard will open in your browser at: http://localhost:8501

📚 API Endpoints

Health Check

GET /

Returns a welcome message with configuration details.

Get All Products (with Filtering)

GET /products?name={name}&category={category}&price={max_price}&order={asc|desc}&limit={limit}

Query Parameters:

• name (optional): Filter by product name (case-insensitive)
• category (optional): Filter by category (laptops, mobiles, accessories, electronics)
• price (optional): Maximum price filter
• order (optional): Sort order - "asc" or "desc" (default: "asc")
• limit (optional): Number of items to return (1-100, default: 10)

Example:

curl "http://127.0.0.1:8000/products?category=laptops&price=50000&order=desc&limit=5"

Get Product by ID

GET /products/{product_id}

Example:

curl "http://127.0.0.1:8000/products/123e4567-e89b-12d3-a456-426614174000"

Create Product

POST /products
Content-Type: application/json

Request Body Example:

{
  "id": "123e4567-e89b-12d3-a456-426614174000",
  "sku": "REAL-135GB-001",
  "name": "Realme 9 Pro 5G",
  "description": "6GB RAM, 128GB Storage, Midnight Black",
  "category": "mobiles",
  "brand": "Realme",
  "price": 17999.0,
  "currency": "INR",
  "discount_percent": 15,
  "stock": 50,
  "is_active": true,
  "rating": 4.5,
  "tags": ["5G", "Android", "Smartphone"],
  "image_urls": ["https://example.com/image1.jpg"],
  "dimensions_cm": {
    "length": 16.4,
    "width": 7.59,
    "height": 0.82
  },
  "seller": {
    "id": "550e8400-e29b-41d4-a716-446655440000",
    "name": "Realme Official Store",
    "email": "support@mistore.in",
    "website": "https://www.realme.com"
  },
  "created_at": "2026-01-16T12:00:00Z"
}

Update Product

PATCH /product/{product_id}
Content-Type: application/json

Request Body Example (partial update):

{
  "price": 16999.0,
  "stock": 45,
  "discount_percent": 20
}

Delete Product

DELETE /products/{product_id}

🏗️ Project Structure

fastapi_ecomerce/
├── app/
│   ├── __init__.py
│   ├── mainn.py              # Main FastAPI application & routes
│   ├── .env                  # Environment variables
│   ├── data/
│   │   └── products.json     # JSON database
│   ├── schema/
│   │   └── product.py        # Pydantic models for validation
│   └── service/
│       └── products.py       # Business logic & data operations
├── scripts/
├── streamlit_app.py          # Streamlit admin dashboard
├── requirements.txt          # Python dependencies
├── LICENSE                   # MIT License
├── .gitignore
└── README.md                 # This file

🔧 Key Components

1. Pydantic Models (app/schema/product.py)

• Product: Main product model with comprehensive validation
• DimensionCm: Product dimensions validation
• Seller: Seller information with email domain validation
• productUpdate: Model for partial updates
• Custom validators for SKU format, business rules, and seller emails

2. Service Layer (app/service/products.py)

• get_all_products(): Retrieve all products
• add_product(): Create a new product with SKU uniqueness check
• remove_product(): Delete a product by ID
• change_product(): Update product with partial data

3. Main API (app/mainn.py)

• FastAPI application setup
• HTTP middleware for request logging
• Dependency injection examples
• Route handlers for all CRUD operations
• Query parameter validation and filtering logic

4. Streamlit Dashboard (streamlit_app.py)

• Home page with overview
• Product catalog with search and filters
• Add new product form
• Update and delete operations

✅ Validation Rules

SKU Format

• Must contain a hyphen (-)
• Must end with exactly 3 digits (e.g., -001)
• Example: REAL-135GB-001

Business Rules

• If stock is 0, is_active must be false
• Products with discount_percent > 0 must have rating > 0

Seller Email Domains

Only these domains are allowed:

• lenovostore.in
• samsungindia.in
• mistore.in
• asusexclusive.in
• hpworld.in
• oneplusstore.in

Product Constraints

• Name: 6-80 characters
• Description: Max 200 characters
• Price: Must be >= 0
• Discount: 0-90%
• Rating: 0-5 stars
• Stock: Must be >= 0
• Tags: Maximum 10 tags

🧪 Testing the API

Using cURL

Get all products:

curl http://127.0.0.1:8000/products

Filter by category:

curl "http://127.0.0.1:8000/products?category=mobiles&limit=5"

Get product by ID:

curl http://127.0.0.1:8000/products/{product_id}

Using Swagger UI

1. Start the FastAPI server
2. Open http://127.0.0.1:8000/docs in your browser
3. Try out the endpoints interactively

🔒 Environment Variables

Create an app/.env file with:

base_url=./app/data/products.json

📦 Dependencies

• fastapi: Modern web framework for building APIs
• uvicorn: ASGI server for running FastAPI
• python-dotenv: Load environment variables from .env
• pydantic: Data validation using Python type annotations
• streamlit: Frontend dashboard framework

🤝 Contributing

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

📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

👨‍💻 Author

Krushna Sonawane

🙏 Acknowledgments

• FastAPI documentation and community
• Pydantic for excellent data validation
• Streamlit for the beautiful dashboard framework

🐛 Known Issues & Future Enhancements

Planned Features

• Database integration (PostgreSQL/MongoDB)
• User authentication and authorization
• Image upload functionality
• Order management system
• Payment gateway integration
• Email notifications
• Advanced analytics dashboard
• API rate limiting
• Caching layer (Redis)
• Unit and integration tests

📧 Support

For issues, questions, or suggestions, please open an issue in the repository.

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Happy Coding! 🚀