framework
FastAPI Errors
FastAPI errors: RequestValidationError (422), HTTPException (custom), missing dependency injection, async DB session lifecycle errors, CORS preflight failures, JWT validation errors.
FastAPI returns 422 with detailed validation errors for malformed inputs (Pydantic). HTTPException is the way to raise typed HTTP errors. Async DB sessions need correct lifecycle (Depends with yield). CORS errors hit on preflight (OPTIONS) — make sure CORSMiddleware is registered before routes. WebSocket close codes (1006, 1011) point at server-side disconnects.
Official docs
https://fastapi.tiangolo.com/tutorial/handling-errors/
Support
https://fastapi.tiangolo.com/help-fastapi/