python-fastapi-conventions

Pattern: FastAPI backend standard structure following async/await patterns.

Usage: Implementing FastAPI routes, models, validation, project initialization.

Instructions:

• Use FastAPI() instance in main.py
• Organize routes in routers/ directory with APIRouter
• Define Pydantic models in models/ with validation
• Use schemas/ for request/response DTOs
• Implement error handling with HTTPException(status_code, detail)
• Use async def for all endpoints (async-first)
• Add type hints on all functions

Structure:

backend/
├── main.py
├── routers/
│   ├── users.py
│   └── items.py
├── models/
│   └── user.py
└── schemas/
    └── user_schema.py

Example Error Handling:

from fastapi import HTTPException

@app.get("/items/{id}")
async def get_item(id: int):
    if not found:
        raise HTTPException(status_code=404, detail="Not found")
    return item