and utilities for concurrency, I/O, hashing, primitives, strings, and more! It
is widely used on most Java projects within Google, and widely used by many
other companies as well.



Guava comes in two flavors:

*   The JRE flavor requires JDK 1.8 or higher.
*   If you need support for Android, use
    [the Android flavor](https://github.com/google/guava/wiki/Android). You can

For example, you might want to try <a href="https://speakeasyapi.dev/?utm_source=fastapi+repo&utm_medium=github+sponsorship" class="external-link" target="_blank">Speakeasy</a>.

There are also several other companies offering similar services that you can search and find online. 🤓

## Generate a TypeScript Frontend Client

Let's start with a simple FastAPI application:

=== "Python 3.9+"

Django REST framework was created to be a flexible toolkit for building Web APIs using Django underneath, to improve its API capabilities.

It is used by many companies including Mozilla, Red Hat and Eventbrite.

It was one of the first examples of **automatic API documentation**, and this was specifically one of the first ideas that inspired "the search for" **FastAPI**.

!!! note

import okhttp3.HttpUrl.Companion.toHttpUrl
import okhttp3.OkHttpClient
import okhttp3.Request
import okhttp3.coroutines.executeAsync
import okhttp3.internal.publicsuffix.PublicSuffixDatabase.Companion.PUBLIC_SUFFIX_RESOURCE
import okio.BufferedSink
import okio.ByteString
import okio.ByteString.Companion.encodeUtf8
import okio.FileSystem
import okio.Path
import okio.Path.Companion.toPath
import okio.buffer

public abstract interface class okhttp3/Dns {
	public static final field Companion Lokhttp3/Dns$Companion;
	public static final field SYSTEM Lokhttp3/Dns;
	public abstract fun lookup (Ljava/lang/String;)Ljava/util/List;
}

public final class okhttp3/Dns$Companion {
}

public abstract class okhttp3/EventListener {
	public static final field Companion Lokhttp3/EventListener$Companion;
	public static final field NONE Lokhttp3/EventListener;

internal fun Long.commonClampToInt(): Int {
  return when {
    this > Int.MAX_VALUE -> Int.MAX_VALUE
    else -> toInt()
  }
}

internal fun CacheControl.Companion.commonForceNetwork() =
  CacheControl.Builder()
    .noCache()
    .build()

internal fun CacheControl.Companion.commonForceCache() =
  CacheControl.Builder()
    .onlyIfCached()
    .maxStale(Int.MAX_VALUE.seconds)
    .build()

         * Avoid shortening reference to enum companion used in enum entry initialization there is no guarantee that the companion object
         * was initialized in advance.
         * For example, When we shorten the following code:
         *     enum class C(val i: Int) {
         *         ONE(<expr>C.K</expr>)  // shorten C.K to K
         *         ;
         *         companion object {
         *             const val K = 1

import java.util.concurrent.Executors
import kotlin.test.assertFailsWith
import okhttp3.TestUtil.threadFactory
import okhttp3.internal.cache2.Relay.Companion.edit
import okhttp3.internal.cache2.Relay.Companion.read
import okio.Buffer
import okio.ByteString
import okio.ByteString.Companion.encodeUtf8
import okio.Pipe
import okio.Source
import okio.buffer
import okio.source
import org.junit.jupiter.api.AfterEach

import javax.net.ServerSocketFactory
import javax.net.SocketFactory
import javax.net.ssl.SSLSocket
import okhttp3.Handshake
import okhttp3.Handshake.Companion.handshake
import okhttp3.TestUtil.threadFactory
import okhttp3.internal.closeQuietly
import okhttp3.testing.PlatformRule
import okio.ByteString.Companion.toByteString
import org.junit.jupiter.api.AfterEach
import org.junit.jupiter.api.BeforeEach
import org.junit.jupiter.api.Test

import okhttp3.FailingCall
import okhttp3.Headers
import okhttp3.Headers.Companion.headersOf
import okhttp3.Protocol
import okhttp3.Request
import okhttp3.Response
import okhttp3.TestUtil.repeat
import okhttp3.internal.concurrent.TaskFaker
import okhttp3.internal.ws.WebSocketExtensions.Companion.parse
import okio.ByteString.Companion.decodeHex
import okio.ByteString.Companion.encodeUtf8
import okio.Pipe
import okio.buffer