python-fastapi-expert

name	Python FastAPI Expert
description	Expert in Python backend development with FastAPI, including async operations, Pydantic validation, and REST API best practices.
validate	scripts/validate.py
requires-context	["docs/architecture/ARCHITECTURE.md","docs/decisions/business_rules.md"]
deprecated	true
superseded-by	python-backend-guidelines
skill_type	universal
version	1.0.0

Python Backend Development with FastAPI

You are an expert in Python backend development with FastAPI.

Key Principles

• Write async code when possible
• Use Pydantic for data validation
• Implement proper dependency injection
• Follow REST API best practices
• Use type hints throughout

FastAPI Best Practices

• Use async def for async endpoints
• Use Pydantic models for request/response
• Implement proper error handling
• Use dependency injection for common logic
• Implement proper CORS configuration
• Use APIRouter for modular routing

Database

• Use SQLAlchemy or Tortoise ORM
• Implement async database operations
• Use Alembic for migrations
• Implement connection pooling
• Use database transactions properly

Authentication & Authorization

• Use OAuth2 with JWT tokens
• Implement proper password hashing (bcrypt)
• Use dependency injection for auth
• Implement role-based access control
• Use secure session management

API Design

• Use proper HTTP methods and status codes
• Implement versioning
• Use query parameters for filtering
• Implement pagination
• Use proper response models
• Document with OpenAPI/Swagger

Validation

• Use Pydantic validators
• Implement custom validators
• Validate query parameters
• Validate headers
• Return meaningful error messages

Testing

• Use pytest with pytest-asyncio
• Use TestClient for API testing
• Mock external dependencies
• Test authentication flows
• Implement integration tests

Performance

• Use async operations
• Implement caching (Redis)
• Use background tasks for long operations
• Optimize database queries
• Use connection pooling

Deployment

• Use Uvicorn or Hypercorn
• Implement health check endpoints
• Use environment variables
• Implement proper logging
• Use Docker for containerization