* **By default**, that would mean that you can only have **one HTTPS certificate per IP address**.
    * No matter how big your server is or how small each application you have on it might be.
    * There is a **solution** to this, however.

    {!> ../../../docs_src/bigger_applications/app/dependencies.py!}
    ```

!!! tip
    We are using an invented header to simplify this example.

    But in real cases you will get better results using the integrated [Security utilities](security/index.md){.internal-link target=_blank}.

## Another module with `APIRouter`

        return {"name": name, "description": "model-a-desc", "foo": model_c}

    client = TestClient(app)
    return client


@needs_pydanticv2
def test_filter_sub_model(client: TestClient):
    response = client.get("/model/modelA")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "name": "modelA",
        "description": "model-a-desc",

* News about FastAPI and friends 🚀
* Guides 📝
* Features ✨
* Breaking changes 🚨
* Tips and tricks ✅

## Follow FastAPI on Twitter

<a href="https://twitter.com/fastapi" class="external-link" target="_blank">Follow @fastapi on **Twitter**</a> to get the latest news about **FastAPI**. 🐦

## Star **FastAPI** in GitHub

I (the author, [@tiangolo](https://twitter.com/tiangolo)) will review it thoroughly and get back to you.

## Public Discussions

Please restrain from publicly discussing a potential security vulnerability. 🙊

It's better to discuss privately and try to find a solution first, to limit the potential impact as much as possible.

---

                    lineDelay: 500
                });
                termynals.push(termynal);
            });
    }

    function loadVisibleTermynals() {
        termynals = termynals.filter(termynal => {
            if (termynal.container.getBoundingClientRect().top - innerHeight <= 0) {
                termynal.init();
                return false;
            }
            return true;
        });

## Future

By this point, it's already clear that **FastAPI** with its ideas is being useful for many people.

It is being chosen over previous alternatives for suiting many use cases better.

Many developers and teams already depend on **FastAPI** for their projects (including me and my team).

But still, there are many improvements and features to come.

**FastAPI** has a great future ahead.

!!! note
    FastAPI will know that the value of `q` is not required because of the default value `= None`.

    The `Union` in `Union[str, None]` will allow your editor to give you better support and detect errors.

## Additional validation

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

### Import `Query` and `Annotated`

And these models are all sharing a lot of the data and duplicating attribute names and types.

We could do better.

We can declare a `UserBase` model that serves as a base for our other models. And then we can make subclasses of that model that inherit its attributes (type declarations, validation, etc).

### Tested

* 100% <abbr title="The amount of code that is automatically tested">test coverage</abbr>.
* 100% <abbr title="Python type annotations, with this your editor and external tools can give you better support">type annotated</abbr> code base.
* Used in production applications.

## Starlette features