### FastAPI Datenfilterung { #fastapi-data-filtering }

FastAPI seinerseits wird den Rückgabetyp sehen und sicherstellen, dass das, was zurückgegeben wird, **nur** diejenigen Felder enthält, welche im Typ deklariert sind.

                * Serialization: you could return an arbitrary object and the
                    `response_model` would be used to serialize that object into the
                    corresponding JSON.
                * Filtering: the JSON sent to the client will only contain the data
                    (fields) defined in the `response_model`. If you returned an object
                    that contains an attribute `password` but the `response_model` does

                    },
                }
            },
            "/response_model_filtering_model-annotation_submodel-return_submodel": {
                "get": {
                    "summary": "Response Model Filtering Model Annotation Submodel Return Submodel",
                    "operationId": "response_model_filtering_model_annotation_submodel_return_submodel_response_model_filtering_model_annotation_submodel_return_submodel_get",

    ]
```

FastAPI will use the return type annotation to perform:

* Data validation
* Automatic documentation
    * It could power automatic client generators
* **Data filtering**

Before this version it was only supported via the `response_model` parameter.

Read more about it in the new docs: [Response Model - Return Type](https://fastapi.tiangolo.com/tutorial/response-model/).