diff --git a/DependencyInjection/Compiler/DiscoveryPass.php b/DependencyInjection/Compiler/DiscoveryPass.php
deleted file mode 100644
index b54e8e02..00000000
--- a/DependencyInjection/Compiler/DiscoveryPass.php
+++ /dev/null
@@ -1,63 +0,0 @@
-<?php
-
-namespace Http\HttplugBundle\DependencyInjection\Compiler;
-
-use Http\Client\HttpClient;
-use Http\Discovery\HttpClientDiscovery;
-use Http\Discovery\MessageFactoryDiscovery;
-use Http\Discovery\StreamFactoryDiscovery;
-use Http\Discovery\UriFactoryDiscovery;
-use Http\Message\MessageFactory;
-use Http\Message\StreamFactory;
-use Http\Message\UriFactory;
-use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
-use Symfony\Component\DependencyInjection\ContainerBuilder;
-
-/**
- * Adds fallback and discovery services.
- *
- * @author Márk Sági-Kazár <mark.sagikazar@gmail.com>
- */
-final class DiscoveryPass implements CompilerPassInterface
-{
-    /**
-     * Fallback services and classes.
-     *
-     * @var array
-     */
-    private $services = [
-        'client' => HttpClient::class,
-        'message_factory' => MessageFactory::class,
-        'uri_factory' => UriFactory::class,
-        'stream_factory' => StreamFactory::class,
-    ];
-
-    /**
-     * Factories by type.
-     *
-     * @var array
-     */
-    private $factoryClasses = [
-        'client' => HttpClientDiscovery::class,
-        'message_factory' => MessageFactoryDiscovery::class,
-        'uri_factory' => UriFactoryDiscovery::class,
-        'stream_factory' => StreamFactoryDiscovery::class,
-    ];
-
-    /**
-     * {@inheritdoc}
-     */
-    public function process(ContainerBuilder $container)
-    {
-        foreach ($this->services as $service => $class) {
-            $serviceId = sprintf('httplug.%s.default', $service);
-
-            if (false === $container->has($serviceId)) {
-                // Register and create factory for service
-                $definition = $container->register($serviceId, $class);
-                $definition->setFactory([$this->factoryClasses[$service], 'find']);
-                $definition->addArgument($class);
-            }
-        }
-    }
-}
diff --git a/HttplugBundle.php b/HttplugBundle.php
index b5402c52..082d32f4 100644
--- a/HttplugBundle.php
+++ b/HttplugBundle.php
@@ -2,8 +2,6 @@
 
 namespace Http\HttplugBundle;
 
-use Http\HttplugBundle\DependencyInjection\Compiler\DiscoveryPass;
-use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 
 /**
@@ -12,10 +10,4 @@
  */
 class HttplugBundle extends Bundle
 {
-    public function build(ContainerBuilder $container)
-    {
-        parent::build($container);
-
-        $container->addCompilerPass(new DiscoveryPass());
-    }
 }
diff --git a/Resources/config/services.xml b/Resources/config/services.xml
index c9b4df13..e34c8425 100644
--- a/Resources/config/services.xml
+++ b/Resources/config/services.xml
@@ -8,7 +8,30 @@
             <tag name="kernel.event_subscriber"/>
         </service>
 
-        <!-- enable autowiring compatibility in Symfony 3.3+ -->
+        <!-- Discovery with autowiring support for Symfony 3.3+ -->
+        <service id="httplug.message_factory.default" class="Http\Message\MessageFactory">
+            <factory class="Http\Discovery\MessageFactoryDiscovery" method="find" />
+        </service>
+        <service id="Http\Message\MessageFactory" alias="httplug.message_factory" public="false" />
+
+        <service id="httplug.stream_factory.default" class="Http\Message\StreamFactory">
+            <factory class="Http\Discovery\StreamFactoryDiscovery" method="find" />
+        </service>
+        <service id="Http\Message\StreamFactory" alias="httplug.stream_factory" public="false" />
+
+        <service id="httplug.uri_factory.default" class="Http\Message\UriFactory">
+            <factory class="Http\Discovery\UriFactoryDiscovery" method="find" />
+        </service>
+        <service id="Http\Message\UriFactory" alias="httplug.uri_factory" public="false" />
+
+        <service id="httplug.async_client.default" class="Http\Client\HttpAsyncClient">
+            <factory class="Http\Discovery\HttpAsyncClientDiscovery" method="find" />
+        </service>
+        <service id="Http\Client\HttpAsyncClient" alias="httplug.async_client.default" public="false" />
+
+        <service id="httplug.client.default" class="Http\Client\HttpClient">
+            <factory class="Http\Discovery\HttpClientDiscovery" method="find" />
+        </service>
         <service id="Http\Client\HttpClient" alias="httplug.client" public="false" />
 
         <!-- ClientFactories -->
diff --git a/Tests/Unit/DependencyInjection/Compiler/DiscoveryPassTest.php b/Tests/Functional/DiscoveryTest.php
similarity index 67%
rename from Tests/Unit/DependencyInjection/Compiler/DiscoveryPassTest.php
rename to Tests/Functional/DiscoveryTest.php
index d84549f9..c016c93d 100644
--- a/Tests/Unit/DependencyInjection/Compiler/DiscoveryPassTest.php
+++ b/Tests/Functional/DiscoveryTest.php
@@ -2,45 +2,58 @@
 
 namespace Http\HttplugBundle\Tests\Unit\DependencyInjection\Compiler;
 
+use Http\Client\HttpAsyncClient;
 use Http\Client\HttpClient;
-use Http\HttplugBundle\DependencyInjection\Compiler\DiscoveryPass;
+use Http\HttplugBundle\DependencyInjection\HttplugExtension;
 use Http\Message\MessageFactory;
 use Http\Message\StreamFactory;
 use Http\Message\UriFactory;
-use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractCompilerPassTestCase;
-use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Matthias\SymfonyDependencyInjectionTest\PhpUnit\AbstractExtensionTestCase;
 use Symfony\Component\DependencyInjection\Definition;
 
 /**
  * @author Márk Sági-Kazár <mark.sagikazar@gmail.com>
  */
-final class DiscoveryPassTest extends AbstractCompilerPassTestCase
+final class DiscoveryTest extends AbstractExtensionTestCase
 {
-    protected function registerCompilerPass(ContainerBuilder $container)
+    protected function setUp()
     {
-        $container->addCompilerPass(new DiscoveryPass());
+        parent::setUp();
+
+        $this->setParameter('kernel.debug', true);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function getContainerExtensions()
+    {
+        return [
+            new HttplugExtension(),
+        ];
     }
 
     public function testDiscoveryFallbacks()
     {
-        $this->compile();
+        $this->load();
 
         $this->assertContainerBuilderHasService('httplug.client.default', HttpClient::class);
         $this->assertContainerBuilderHasService('httplug.message_factory.default', MessageFactory::class);
         $this->assertContainerBuilderHasService('httplug.uri_factory.default', UriFactory::class);
         $this->assertContainerBuilderHasService('httplug.stream_factory.default', StreamFactory::class);
+        $this->assertContainerBuilderHasService('httplug.async_client.default', HttpAsyncClient::class);
     }
 
     public function testDiscoveryPartialFallbacks()
     {
+        $this->load();
         $this->setDefinition('httplug.client.default', new Definition('Http\Adapter\Guzzle6\Client'));
 
-        $this->compile();
-
         $this->assertContainerBuilderHasService('httplug.client.default', 'Http\Adapter\Guzzle6\Client');
         $this->assertContainerBuilderHasService('httplug.message_factory.default', MessageFactory::class);
         $this->assertContainerBuilderHasService('httplug.uri_factory.default', UriFactory::class);
         $this->assertContainerBuilderHasService('httplug.stream_factory.default', StreamFactory::class);
+        $this->assertContainerBuilderHasService('httplug.async_client.default', HttpAsyncClient::class);
     }
 
     public function testNoDiscoveryFallbacks()
@@ -49,7 +62,8 @@ public function testNoDiscoveryFallbacks()
         $this->setDefinition('httplug.message_factory.default', new Definition(MessageFactory::class));
         $this->setDefinition('httplug.uri_factory.default', new Definition(UriFactory::class));
         $this->setDefinition('httplug.stream_factory.default', new Definition(StreamFactory::class));
+        $this->setDefinition('httplug.async_client.default', new Definition(HttpAsyncClient::class));
 
-        $this->compile();
+        $this->load();
     }
 }