Auf dem Requestpfad läuft die *äußerste* Middleware zuerst.

Auf dem Responsepfad läuft sie zuletzt.

Zum Beispiel:

```Python
app.add_middleware(MiddlewareA)

class CustomModel(BaseModel):
    a: int


app = FastAPI()

callback_router = APIRouter(default_response_class=JSONResponse)


@callback_router.get(
    "{$callback_url}/callback/", responses={400: {"model": CustomModel}}
)
def callback_route():
    pass  # pragma: no cover


@app.post("/", callbacks=callback_router.routes)
def main_route(callback_url: HttpUrl):

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles

app = FastAPI()

from fastapi import FastAPI

app = FastAPI(docs_url="/documentation", redoc_url=None)


@app.get("/items/")
async def read_items():

from fastapi import FastAPI

app = FastAPI()


@app.post("/index-weights/")
async def create_index_weights(weights: dict[int, float]):

from fastapi import FastAPI

app = FastAPI(openapi_url="/api/v1/openapi.json")


@app.get("/items/")
async def read_items():

from fastapi import FastAPI, status

app = FastAPI()


@app.post("/items/", status_code=status.HTTP_201_CREATED)
async def create_item(name: str):

from fastapi import FastAPI
from fastapi.responses import UJSONResponse

app = FastAPI()


@app.get("/items/", response_class=UJSONResponse)
async def read_items():

from fastapi import FastAPI

app = FastAPI()


@app.get("/keyword-weights/", response_model=dict[str, float])
async def read_keyword_weights():

from fastapi import FastAPI
from fastapi.responses import RedirectResponse

app = FastAPI()


@app.get("/typer")
async def redirect_typer():