So, it was a complete additional system.

It is not very popular or used nowadays.

## OpenAPI { #openapi }

OpenAPI (previously known as Swagger) is the open specification for building APIs (now part of the Linux Foundation).

**FastAPI** is based on **OpenAPI**.

That's what makes it possible to have multiple automatic interactive documentation interfaces, code generation, etc.

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

/** Collectors utilities for {@code common.collect.Table} internals. */
@GwtCompatible
@IgnoreJRERequirement // used only from APIs with Java 8 types in them
final class TableCollectors {

  static <T extends @Nullable Object, R, C, V>
      Collector<T, ?, ImmutableTable<R, C, V>> toImmutableTable(
          Function<? super T, ? extends R> rowFunction,

			return nil, cred
		}
	}
	writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrAccessDenied), r.URL)
	return nil, auth.Credentials{}
}

// AdminError - is a generic error for all admin APIs.
type AdminError struct {
	Code       string
	Message    string
	StatusCode int
}

func (ae AdminError) Error() string {
	return ae.Message
}

import okhttp3.internal.http.RecordingProxySelector
import okhttp3.tls.HandshakeCertificates
import okhttp3.tls.internal.TlsUtil.localhost

/**
 * OkHttp is usually tested with functional tests: these use public APIs to confirm behavior against
 * MockWebServer. In cases where logic is particularly tricky, we use unit tests. This class makes
 * it easy to get sample values to use in such tests.
 *

    try {
      helper = new SafeAtomicHelper();
    } catch (Throwable reflectionFailure) { // sneaky checked exception
      // Some Android 5.0.x Samsung devices have bugs in JDK reflection APIs that cause
      // getDeclaredField to throw a NoSuchFieldException when the field is definitely there.
      // For these users fallback to a suboptimal implementation, based on synchronized. This will

---

"_Si vous cherchez à apprendre un **framework moderne** pour créer des APIs REST, regardez **FastAPI** [...] C'est rapide, facile à utiliser et à apprendre [...]_"

"_Nous sommes passés à **FastAPI** pour nos **APIs** [...] Je pense que vous l'aimerez [...]_"

    * **Robuste** : Obtenez du code prêt pour être utilisé en production. Avec de la documentation automatique interactive.
    * **Basé sur des normes** : Basé sur (et totalement compatible avec) les normes ouvertes pour les APIs : <a href="https://github.com/OAI/OpenAPI-Specification" class="external-link" target="_blank">OpenAPI</a> et <a href="https://json-schema.org/" class="external-link" target="_blank">JSON Schema</a>.

> ¿Cuál es la historia de este proyecto? Parece haber surgido de la nada y ser increíble en pocas semanas [...]

Aquí hay un poquito de esa historia.

## Alternativas

He estado creando APIs con requisitos complejos durante varios años (Machine Learning, sistemas distribuidos, trabajos asíncronos, bases de datos NoSQL, etc.), liderando varios equipos de desarrolladores.

> What’s the history of this project? It seems to have come from nowhere to awesome in a few weeks [...]

Here's a little bit of that history.

## Alternatives { #alternatives }

I have been creating APIs with complex requirements for several years (Machine Learning, distributed systems, asynchronous jobs, NoSQL databases, etc), leading several teams of developers.

As part of that, I needed to investigate, test and use many alternatives.

 *
 * <ul>
 *   <li>Memory footprint has a fixed overhead (about 24 bytes per instance).
 *   <li><i>Some</i> construction use cases force the data to be copied (though several construction
 *       APIs are offered that don't).
 *   <li>Can't be passed directly to methods that expect {@code long[]} (though the most common
 *       utilities do have replacements here).
 *   <li>Dependency on {@code com.google.common} / Guava.