from typing import Any import orjson from fastapi import FastAPI, Response app = FastAPI() class CustomORJSONResponse(Response): media_type = "application/json" def render(self, content: Any) -> bytes: assert orjson is not None, "orjson must be installed" return orjson.dumps(content, option=orjson.OPT_INDENT_2) @app.get("/", response_class=CustomORJSONResponse) async def main(): return {"message": "Hello World"}