fastapi/docs/en/docs/reference/responses.md

Custom Response Classes - File, HTML, Redirect, Streaming, etc.

There are several custom response classes you can use to create an instance and return them directly from your path operations.

Read more about it in the FastAPI docs for Custom Response - HTML, Stream, File, others.

You can import them directly from fastapi.responses:

from fastapi.responses import (
    FileResponse,
    HTMLResponse,
    JSONResponse,
    ORJSONResponse,
    PlainTextResponse,
    RedirectResponse,
    Response,
    StreamingResponse,
    UJSONResponse,
)

FastAPI Responses

There were a couple of custom FastAPI response classes that were intended to optimize JSON performance.

However, they are now deprecated as you will now get better performance by using a Response Model - Return Type.

That way, Pydantic will serialize the data into JSON bytes on the Rust side, which will achieve better performance than these custom JSON responses.

Read more about it in Custom Response - HTML, Stream, File, others - orjson or Response Model.

::: fastapi.responses.UJSONResponse options: members: - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie

::: fastapi.responses.ORJSONResponse options: members: - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie

Starlette Responses

You can read more about all of them in the FastAPI docs for Custom Response and in the Starlette docs about Responses.

::: fastapi.responses.FileResponse options: members: - chunk_size - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie

::: fastapi.responses.HTMLResponse options: members: - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie

::: fastapi.responses.JSONResponse options: members: - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie

::: fastapi.responses.PlainTextResponse options: members: - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie

::: fastapi.responses.RedirectResponse options: members: - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie

::: fastapi.responses.Response options: members: - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie

::: fastapi.responses.StreamingResponse options: members: - body_iterator - charset - status_code - media_type - body - background - raw_headers - render - init_headers - headers - set_cookie - delete_cookie