FastAPI Interview Prep
4 min read Quiz at the end
Interview topics: ASGI, Pydantic v2, Depends, sync vs async, OpenAPI auto-docs, lifespan.
FastAPI Interview Topics
- ASGI vs WSGI — ASGI supports async; FastAPI is ASGI via Uvicorn
- Pydantic v2 — faster, uses Rust core; model_dump() replaces dict()
- Dependency Injection — Depends() injects shared logic (auth, DB)
- Path vs Query params — path params in URL; query params after ?
- Background tasks vs Celery — BackgroundTasks for lightweight; Celery for heavy
- Sync vs Async endpoints — async for I/O; sync for CPU (runs in threadpool)
- OpenAPI auto-docs — generated from type hints and Pydantic models at /docs
Topic Quiz · 3 questions
Test your understanding before moving on
1. What does ASGI stand for?
💡 ASGI is the async successor to WSGI for Python web apps.
2. What is Pydantic v2 main improvement?
💡 Pydantic v2 uses a Rust-based core (pydantic-core) for much faster validation.
3. What does OpenAPI auto-docs provide?
💡 The /docs Swagger UI shows all endpoints, schemas, and lets you make test API calls.