@app.get("/by-alias/dict", response_model=Model)
def by_alias_dict():
    return {"alias": "Foo"}


@app.get("/by-alias/model", response_model=Model)
def by_alias_model():
    return Model(alias="Foo")


@app.get("/by-alias/list", response_model=List[Model])
def by_alias_list():
    return [{"alias": "Foo"}, {"alias": "Bar"}]


@app.get("/no-alias/dict", response_model=ModelNoAlias)
def no_alias_dict():
    return {"name": "Foo"}

And it can return anything you want.

In this case, this dependency expects:

* An optional query parameter `q` that is a `str`.
* An optional query parameter `skip` that is an `int`, and by default is `0`.
* An optional query parameter `limit` that is an `int`, and by default is `100`.

And then it just returns a `dict` containing those values.

!!! info
    FastAPI added support for `Annotated` (and started recommending it) in version 0.95.0.

You can "star" FastAPI in GitHub (clicking the star button at the top right): <a href="https://github.com/tiangolo/fastapi" class="external-link" target="_blank">https://github.com/tiangolo/fastapi</a>. ⭐️

By adding a star, other users will be able to find it more easily and see that it has been already useful for others.

## Watch the GitHub repository for releases

# Request Files

You can define files to be uploaded by the client using `File`.

!!! info
    To receive uploaded files, first install <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

    E.g. `pip install python-multipart`.

    This is because uploaded files are sent as "form data".

## Import `File`

Import `File` and `UploadFile` from `fastapi`:

=== "Python 3.9+"

    ```

=== "Python 3.8+"

    ```Python
    q: Annotated[Union[str, None]] = None
    ```

Both of those versions mean the same thing, `q` is a parameter that can be a `str` or `None`, and by default, it is `None`.

Now let's jump to the fun stuff. 🎉

## Add `Query` to `Annotated` in the `q` parameter

# Custom Response - HTML, Stream, File, others

By default, **FastAPI** will return the responses using `JSONResponse`.

You can override it by returning a `Response` directly as seen in [Return a Response directly](response-directly.md){.internal-link target=_blank}.

They are normally used to declare specific security permissions, for example:

* `users:read` or `users:write` are common examples.
* `instagram_basic` is used by Facebook / Instagram.
* `https://www.googleapis.com/auth/drive` is used by Google.

!!! info
    In OAuth2 a "scope" is just a string that declares a specific permission required.

    It doesn't matter if it has other characters like `:` or if it is a URL.

* the data from the client to be sent through the network
* the data sent by your program to be received by the client through the network
* the contents of a file in the disk to be read by the system and given to your program
* the contents your program gave to the system to be written to disk
* a remote API operation
* a database operation to finish

Each "scope" is just a string (without spaces).

They are normally used to declare specific security permissions, for example:

* `users:read` or `users:write` are common examples.
* `instagram_basic` is used by Facebook / Instagram.
* `https://www.googleapis.com/auth/drive` is used by Google.

!!! info

To understand more about it, see the section <a href="https://fastapi.tiangolo.com/benchmarks/" class="internal-link" target="_blank">Benchmarks</a>.

## Dependencies

Used by Pydantic: