Sie können die `APIRouter`-Klasse direkt von `fastapi` importieren:

```python
from fastapi import APIRouter
```

::: fastapi.APIRouter
    options:
        members:
            - websocket
            - include_router
            - get
            - put
            - post
            - delete
            - options
            - head
            - patch
            - trace

You can import the `APIRouter` class directly from `fastapi`:

```python
from fastapi import APIRouter
```

::: fastapi.APIRouter
    options:
        members:
            - websocket
            - include_router
            - get
            - put
            - post
            - delete
            - options
            - head
            - patch
            - trace

from fastapi import APIRouter, Body

router = APIRouter()


@router.post("/compute")
def compute(a: int = Body(), b: str = Body()):

  }

  public void testConverter_nullConversions() {
    for (CaseFormat outer : CaseFormat.values()) {
      for (CaseFormat inner : CaseFormat.values()) {
        assertNull(outer.converterTo(inner).convert(null));
        assertNull(outer.converterTo(inner).reverse().convert(null));
      }
    }
  }

  public void testConverter_toString() {
    assertEquals(

    options:
        members:
            - openapi_version
            - webhooks
            - state
            - dependency_overrides
            - openapi
            - websocket
            - include_router
            - get
            - put
            - post
            - delete
            - options
            - head
            - patch
            - trace
            - on_event
            - middleware

        then:
        name == 'org.gradle.SomeClass.Outer.Sibling'
        _ * classMetaData.innerClassNames >> []
        _ * classMetaData.outerClassName >> 'org.gradle.SomeClass.Outer'
        _ * metaDataRepository.get('org.gradle.SomeClass.Outer') >> outerClass
        _ * outerClass.innerClassNames >> ['org.gradle.SomeClass.Outer.Sibling']
    }

    def resolvesUnqualifiedNameToJavaLangPackage() {

```Python hl_lines="35"
{!../../../docs_src/openapi_callbacks/tutorial001.py!}
```

!!! tip "Tipp"
    Beachten Sie, dass Sie nicht den Router selbst (`invoices_callback_router`) an `callback=` übergeben, sondern das Attribut `.routes`, wie in `invoices_callback_router.routes`.

### Es in der Dokumentation ansehen

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):
    pass  # pragma: no cover

	"testing"

	"github.com/minio/mux"
)

// Test cross domain xml handler.
func TestCrossXMLHandler(t *testing.T) {
	// Server initialization.
	router := mux.NewRouter().SkipClean(true).UseEncodedPath()
	handler := setCrossDomainPolicyMiddleware(router)
	srv := httptest.NewServer(handler)

	resp, err := http.Get(srv.URL + crossDomainXMLEntity)
	if err != nil {
		t.Fatal(err)
	}

```

## Benutzerdefinierte `APIRoute`-Klasse in einem Router

Sie können auch den Parameter `route_class` eines `APIRouter` festlegen:

```Python hl_lines="26"
{!../../../docs_src/custom_request_and_route/tutorial003.py!}
```