fastapi-patterns

# FastAPI Patterns Skill

Provides comprehensive FastAPI development patterns and best practices for building modern, production-ready Python APIs.

## When to Use This Skill

Activate this skill when working with:
- FastAPI application architecture and design
- Pydantic models and data validation
- SQLAlchemy ORM patterns and relationships
- Async/await patterns and performance optimization
- Dependency injection and middleware
- JWT authentication and authorization
- API documentation and OpenAPI schemas

## Quick Reference

### Development Commands
```bash
# Development server with auto-reload
uvicorn main:app --reload --host 0.0.0.0 --port 8000

# Production with workers
uvicorn main:app --host 0.0.0.0 --port 8000 --workers 4

# With Gunicorn (recommended for production)
gunicorn main:app -w 4 -k uvicorn.workers.UvicornWorker -b 0.0.0.0:8000

# Install dependencies
pip install fastapi uvicorn[standard] sqlalchemy pydantic-settings python-jose passlib bcrypt

# Run tests
pytest tests/ -v --cov=app
```

## Application Structure

```
app/
├── main.py                 # Application entry point
├── config.py              # Settings and configuration
├── dependencies.py        # Dependency injection
├── database.py           # Database connection
├── models/               # SQLAlchemy models
│   ├── __init__.py
│   ├── user.py
│   ├── organization.py
│   └── base.py
├── schemas/              # Pydantic schemas
│   ├── __init__.py
│   ├── user.py
│   └── organization.py
├── routers/              # API endpoints
│   ├── __init__.py
│   ├── auth.py
│   ├── users.py
│   └── organizations.py
├── services/             # Business logic
│   ├── __init__.py
│   ├── auth_service.py
│   └── user_service.py
├── middleware/           # Custom middleware
│   └── auth.py
└── utils/               # Utility functions
    ├── security.py
    └── validators.py
```

## Application Setup with Lifespan

```python
# main.py
from fastapi import FastAPI
from fastapi.middleware.cors import CORS