backend-python

Backend Python Skill

Core Principles

• Async throughout: Mixing sync and async in FastAPI causes thread pool starvation.
• Lifespan context manager: Use for startup/shutdown — on_event is deprecated.
• Pydantic for all I/O: Request bodies, response models, config — single source of truth.
• One pool per process: Connection pools are singletons, never per-request.
• Type annotations everywhere: Python is typed now; use it.

References

• references/fastapi-patterns.md — DI, Pydantic v2, background tasks, async middleware
• references/django-patterns.md — Models, DRF, signals, migrations, admin customization
• references/sqlalchemy-patterns.md — Session management, eager/lazy loading, async, Alembic
• references/async-python.md — asyncio, aiohttp, concurrent.futures, structured concurrency

Scripts

• scripts/detect-python-stack.sh — Reads requirements.txt/pyproject.toml to identify stack