For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder`

Let's imagine that you have a database `fake_db` that only receives JSON compatible data.

For example, it doesn't receive `datetime` objects, as those are not compatible with JSON.

from fastapi import FastAPI, Request

app = FastAPI(
    servers=[
        {"url": "https://stag.example.com", "description": "Staging environment"},
        {"url": "https://prod.example.com", "description": "Production environment"},
    ],
    root_path="/api/v1",
    root_path_in_servers=False,
)


@app.get("/app")
def read_main(request: Request):

 * but was not itself a public suffix. However, this test is no longer accurate. There are many
 * domains which are both public suffixes and addressable as hosts; {@code "uk.com"} is one example.
 * Using the subset of public suffixes that are {@linkplain #isRegistrySuffix() registry suffixes},
 * one can get a better result, as only a few registry suffixes are addressable. However, the most

			WantException:  true,
		},
		{ // case 11
			Args:           strings.Split("envoy --selector app=example --browser=false", " "),
			ExpectedRegexp: regexp.MustCompile(".*no pods found"),
			WantException:  true,
		},
		{ // case 12
			Args:           strings.Split("envoy --browser=false --selector app=example pod-123456-7890", " "),
			ExpectedRegexp: regexp.MustCompile(".*Error: name cannot be provided when a selector is specified"),

def get_settings_override():
    return Settings(admin_email="testing_admin@example.com")


app.dependency_overrides[get_settings] = get_settings_override


def test_app():
    response = client.get("/info")
    data = response.json()
    assert data == {
        "app_name": "Awesome API",
        "admin_email": "testing_admin@example.com",
        "items_per_user": 50,

   * empty strings from the results. For example, {@code
   * Splitter.on(',').omitEmptyStrings().split(",a,,,b,c,,")} returns an iterable containing only
   * {@code ["a", "b", "c"]}.
   *
   * <p>If either {@code trimResults} option is also specified when creating a splitter, that
   * splitter always trims results first before checking for emptiness. So, for example, {@code

                "description": "Staging but actually localhost still",
            },
            {
                "url": IsOneOf(
                    "https://prod.example.com/",
                    # TODO: remove when deprecating Pydantic v1
                    "https://prod.example.com",
                )
            },
        ],
        "paths": {
            "/foo": {
                "get": {
                    "summary": "Foo",

The same example from above, returning an `HTMLResponse`, could look like:

```Python hl_lines="2  7  19"
{!../../docs_src/custom_response/tutorial003.py!}
```

/// warning

A `Response` returned directly by your *path operation function* won't be documented in OpenAPI (for example, the `Content-Type` won't be documented) and won't be visible in the automatic interactive docs.

To achieve this, you will normally have a **separate program** that would make sure your application is run on startup. And in many cases, it would also make sure other components or applications are also run, for example, a database.

### Example Tools to Run at Startup

Some examples of the tools that can do this job are:

* Docker
* Kubernetes
* Docker Compose
* Docker in Swarm Mode
* Systemd
* Supervisor

    "tax": 3.2,
    "tags": [
        "rock",
        "metal",
        "bar"
    ],
    "images": [
        {
            "url": "http://example.com/baz.jpg",
            "name": "The Foo live"
        },
        {
            "url": "http://example.com/dave.jpg",
            "name": "The Baz"
        }
    ]
}
```

/// info