The main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank} should be enough to give you a tour through all the main features of **FastAPI**.

In the next sections you will see other options, configurations, and additional features.

!!! tip
    The next sections are **not necessarily "advanced"**.

    And it's possible that for your use case, the solution is in one of them.

## Read the Tutorial first

 *     logger.info("Done with {0}", name);
 *   }
 * }, executor);
 * }</pre>
 *
 * <h3>How to get an instance</h3>
 *
 * <p>We encourage you to return {@code ListenableFuture} from your methods so that your users can
 * take advantage of the {@linkplain Futures utilities built atop the class}. The way that you will
 * create {@code ListenableFuture} instances depends on how you currently create {@code Future}
 * instances:

FastAPI will use this return type to:

* **Validate** the returned data.
    * If the data is invalid (e.g. you are missing a field), it means that *your* app code is broken, not returning what it should, and it will return a server error instead of returning incorrect data. This way you and your clients can be certain that they will receive the data and the data shape expected.
* Add a **JSON Schema** for the response, in the OpenAPI *path operation*.

But then the attackers try with username `stanleyjobsox` and password `love123`.

And your application code does something like:

```Python
if "stanleyjobsox" == "stanleyjobson" and "love123" == "swordfish":
    ...
```

contributors and maintainers pledge to make participation in our project and our
community a harassment-free experience for everyone, regardless of age, body
size, disability, ethnicity, gender identity and expression, level of
experience, nationality, personal appearance, race, religion, or sexual identity
and orientation.

## Our Standards

Examples of behavior that contributes to creating a positive environment include:

func ExpectedExpiryTime(modTime time.Time, days int) time.Time {
	if days == 0 {
		return modTime
	}
	t := modTime.UTC().Add(time.Duration(days+1) * 24 * time.Hour)
	return t.Truncate(24 * time.Hour)
}

// SetPredictionHeaders sets time to expiry and transition headers on w for a
// given obj.
func (lc Lifecycle) SetPredictionHeaders(w http.ResponseWriter, obj ObjectOpts) {

			ondisk:        false,
		},
		{
			// restore completed but expired
			restoreStatus: completedRestoreObj(time.Now().Add(-time.Hour)),
			ondisk:        false,
		},
		{
			// restore completed
			restoreStatus: completedRestoreObj(time.Now().Add(time.Hour)),
			ondisk:        true,
		},
	}

	for i, tc := range testCases {
		if actual := tc.restoreStatus.OnDisk(); actual != tc.ondisk {

Do you want to have an `id` and `email` and not have any `username` in your model? Sure. You can use these same tools.

Do you want to just have a `str`? Or just a `dict`? Or a database class model instance directly? It all works the same way.

You actually don't have users that log in to your application but robots, bots, or other systems, that have just an access token? Again, it all works the same.

In our code example above, we don't use it directly, but we pass it to FastAPI for it to use it.

The `lifespan` parameter of the `FastAPI` app takes an **async context manager**, so we can pass our new `lifespan` async context manager to it.

```Python hl_lines="22"
{!../../../docs_src/events/tutorial003.py!}
```

 *     logger.info("Done with {0}", name);
 *   }
 * }, executor);
 * }</pre>
 *
 * <h3>How to get an instance</h3>
 *
 * <p>We encourage you to return {@code ListenableFuture} from your methods so that your users can
 * take advantage of the {@linkplain Futures utilities built atop the class}. The way that you will
 * create {@code ListenableFuture} instances depends on how you currently create {@code Future}
 * instances: