Por ejemplo, vamos a añadir <a href="https://github.com/Rebilly/ReDoc/blob/master/docs/redoc-vendor-extensions.md#x-logo" class="external-link" target="_blank">la extensión OpenAPI de ReDoc para incluir un logo personalizado</a>.

### **FastAPI** normal

Primero, escribe toda tu aplicación **FastAPI** como normalmente:

import org.jspecify.annotations.Nullable;

/**
 * A {@link Collection} whose contents will never change, and which offers a few additional
 * guarantees detailed below.
 *
 * <p><b>Warning:</b> avoid <i>direct</i> usage of {@link ImmutableCollection} as a type (just as
 * with {@link Collection} itself). Prefer subtypes such as {@link ImmutableSet} or {@link
 * ImmutableList}, which have well-defined {@link #equals} semantics, thus avoiding a common source

import org.jspecify.annotations.Nullable;

/**
 * Abstract {@link ListeningExecutorService} implementation that creates {@link ListenableFuture}
 * instances for each {@link Runnable} and {@link Callable} submitted to it. These tasks are run
 * with the abstract {@link #execute execute(Runnable)} method.
 *
 * <p>In addition to {@link #execute}, subclasses must implement all methods related to shutdown and
 * termination.
 *

 * bimap containing the same entries as this bimap but with reversed keys and values.
 *
 * <h3>Implementations</h3>
 *
 * <ul>
 *   <li>{@link ImmutableBiMap}
 *   <li>{@link HashBiMap}
 *   <li>{@link EnumBiMap}
 *   <li>{@link EnumHashBiMap}
 * </ul>
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.
 *

import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.jspecify.annotations.Nullable;

/**
 * An {@link ExecutorService} that returns {@link ListenableFuture} instances. To create an instance
 * from an existing {@link ExecutorService}, call {@link
 * MoreExecutors#listeningDecorator(ExecutorService)}.
 *
 * @author Chris Povirk
 * @since 10.0
 */
@DoNotMock(

👐, Uvicorn ⏳ 🕴 🔗 ⏮️ ✳, &amp; ⚫️ 🛎 ⚙️ <a href="https://github.com/MagicStack/uvloop" class="external-link" target="_blank">`uvloop`</a>, ↕-🎭 💧-♻ `asyncio`.

import java.util.stream.Collector;
import org.jspecify.annotations.Nullable;

/**
 * A {@link NavigableSet} whose contents will never change, with many other important properties
 * detailed at {@link ImmutableCollection}.
 *
 * <p><b>Warning:</b> as with any sorted collection, you are strongly advised not to use a {@link
 * Comparator} or {@link Comparable} type whose comparison behavior is <i>inconsistent with

Y las siguientes secciones asumen que ya lo leíste y que conoces esas ideas principales.

## Cursos externos

También puedes declarar responses adicionales con sus modelos, códigos de estado, etc.

Hay un capítulo entero en la documentación sobre ello, puedes leerlo en [Responses Adicionales en OpenAPI](additional-responses.md){.internal-link target=_blank}.

## OpenAPI Extra

Cuando declaras una *path operation* en tu aplicación, **FastAPI** genera automáticamente los metadatos relevantes sobre esa *path operation* para incluirlos en el esquema de OpenAPI.

Para hacerlo, usa el type hint estándar de Python <a href="https://docs.python.org/3/library/typing.html#typing.Union" class="external-link" target="_blank">`typing.Union`</a>:

/// note | Nota