and binds an identifier, the <i>type name</i>, to it.
</p>

<pre class="ebnf">
TypeDef = identifier [ TypeParameters ] Type .
</pre>

<p>
The new type is called a <i>defined type</i>.
It is <a href="#Type_identity">different</a> from any other type,
including the type it is created from.
</p>

<pre>
type (

```

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/).

### Docs