from fastapi import FastAPI, HTTPException from fastapi.exceptions import RequestValidationError from fastapi.responses import PlainTextResponse from starlette.exceptions import HTTPException as StarletteHTTPException app = FastAPI() @app.exception_handler(StarletteHTTPException) async def http_exception_handler(request, exc): return PlainTextResponse(str(exc.detail), status_code=exc.status_code) @app.exception_handler(RequestValidationError) async def validation_exception_handler(request, exc): return PlainTextResponse(str(exc), status_code=400) @app.get("/items/{item_id}") async def read_item(item_id: int): if item_id == 3: raise HTTPException(status_code=418, detail="Nope! I don't like 3.") return {"item_id": item_id}