🧾 FastAPI Billing API

REST API for billing management built with FastAPI, PostgreSQL, Docker Compose, and SQLAlchemy. Allows client registration and invoice creation through clear, automatically documented endpoints.

---

📌 Features

• ✅ Create and list clients
• ✅ Create and list invoices
• ✅ SQLAlchemy ORM integration
• ✅ Pydantic validation
• ✅ Automatic Swagger/ReDoc documentation
• ✅ Fully containerized with Docker
• ✅ Comprehensive testing with Pytest
• ✅ Database connection waiting with Dockerize

---

🏗️ Project Structure

fastapi-billing-api/
├── app/
│   ├── __init__.py
│   ├── crud.py          # Database operations
│   ├── database.py      # Database configuration
│   ├── main.py          # FastAPI application
│   ├── models.py        # SQLAlchemy models
│   └── schemas.py       # Pydantic schemas
├── tests/
│   └── test_api.py      # API tests
├── Dockerfile           # Container configuration
├── docker-compose.yml   # Multi-service setup
├── requirements.txt     # Python dependencies
└── README.md

---

🚀 Getting Started

Prerequisites

• Docker and Docker Compose
• Git

1. Clone the Repository

git clone https://github.com/yourusername/fastapi-billing-api.git
cd fastapi-billing-api

2. Start the Application

docker compose up --build

The API will be available at:

• API Documentation: http://localhost:8000/docs
• Alternative Docs: http://localhost:8000/redoc
• API Base URL: http://localhost:8000

3. Stop the Application

docker compose down

---

📬 API Endpoints

🔸 Clients

➕ Create Client

POST /clients/
Content-Type: application/json

{
  "name": "John Doe",
  "email": "john@example.com"
}

📋 List Clients

GET /clients/

🔸 Invoices

➕ Create Invoice

POST /invoices/
Content-Type: application/json

{
  "amount": 1250.50,
  "client_id": 1
}

📋 List Invoices

GET /invoices/

---

🧪 Running Tests

Make sure the database is running:

docker compose up -d db

Run the test suite:

docker compose run --rm web pytest

Run tests with coverage:

docker compose run --rm web pytest --cov=app

---

🛠️ Development

Environment Variables

The application uses the following environment variables:

• DATABASE_URL: PostgreSQL connection string (automatically set in Docker Compose)

Local Development

For local development with hot reload:

docker compose up

---

🔧 Technologies Used

• FastAPI - Modern Python web framework
• PostgreSQL 15 - Relational database
• SQLAlchemy - Python ORM
• Pydantic - Data validation
• Docker - Containerization
• Pytest - Testing framework
• Dockerize - Database connection waiting

---