diff --git a/src/Symfony/Component/Messenger/CHANGELOG.md b/src/Symfony/Component/Messenger/CHANGELOG.md
index 814e1625dc6a5..3cf43252be713 100644
--- a/src/Symfony/Component/Messenger/CHANGELOG.md
+++ b/src/Symfony/Component/Messenger/CHANGELOG.md
@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+5.3.0
+-----
+
+* `InMemoryTransport` can perform message serialization through dsn `in-memory://?serialize=true`.
+
 5.2.0
 -----
 
diff --git a/src/Symfony/Component/Messenger/Tests/Transport/InMemoryTransportFactoryTest.php b/src/Symfony/Component/Messenger/Tests/Transport/InMemoryTransportFactoryTest.php
index 6fe95025cd583..adb089efaa533 100644
--- a/src/Symfony/Component/Messenger/Tests/Transport/InMemoryTransportFactoryTest.php
+++ b/src/Symfony/Component/Messenger/Tests/Transport/InMemoryTransportFactoryTest.php
@@ -49,6 +49,35 @@ public function testCreateTransport()
         $this->assertInstanceOf(InMemoryTransport::class, $this->factory->createTransport('in-memory://', [], $serializer));
     }
 
+    public function testCreateTransportWithoutSerializer()
+    {
+        /** @var SerializerInterface $serializer */
+        $serializer = $this->createMock(SerializerInterface::class);
+        $serializer
+            ->expects($this->never())
+            ->method('encode')
+        ;
+        $transport = $this->factory->createTransport('in-memory://?serialize=false', [], $serializer);
+        $message = Envelope::wrap(new DummyMessage('Hello.'));
+        $transport->send($message);
+
+        $this->assertSame([$message], $transport->get());
+    }
+
+    public function testCreateTransportWithSerializer()
+    {
+        /** @var SerializerInterface $serializer */
+        $serializer = $this->createMock(SerializerInterface::class);
+        $message = Envelope::wrap(new DummyMessage('Hello.'));
+        $serializer
+            ->expects($this->once())
+            ->method('encode')
+            ->with($this->equalTo($message))
+        ;
+        $transport = $this->factory->createTransport('in-memory://?serialize=true', [], $serializer);
+        $transport->send($message);
+    }
+
     public function testResetCreatedTransports()
     {
         $transport = $this->factory->createTransport('in-memory://', [], $this->createMock(SerializerInterface::class));
@@ -63,6 +92,8 @@ public function provideDSN(): array
     {
         return [
             'Supported' => ['in-memory://foo'],
+            'Serialize enabled' => ['in-memory://?serialize=true'],
+            'Serialize disabled' => ['in-memory://?serialize=false'],
             'Unsupported' => ['amqp://bar', false],
         ];
     }
diff --git a/src/Symfony/Component/Messenger/Tests/Transport/InMemoryTransportTest.php b/src/Symfony/Component/Messenger/Tests/Transport/InMemoryTransportTest.php
index 6fddc3fbbc3e5..733eeb97714c7 100644
--- a/src/Symfony/Component/Messenger/Tests/Transport/InMemoryTransportTest.php
+++ b/src/Symfony/Component/Messenger/Tests/Transport/InMemoryTransportTest.php
@@ -14,7 +14,9 @@
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Messenger\Envelope;
 use Symfony\Component\Messenger\Tests\Fixtures\AnEnvelopeStamp;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
 use Symfony\Component\Messenger\Transport\InMemoryTransport;
+use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;
 
 /**
  * @author Gary PEGEOT <garypegeot@gmail.com>
@@ -26,9 +28,21 @@ class InMemoryTransportTest extends TestCase
      */
     private $transport;
 
+    /**
+     * @var InMemoryTransport
+     */
+    private $serializeTransport;
+
+    /**
+     * @var SerializerInterface
+     */
+    private $serializer;
+
     protected function setUp(): void
     {
+        $this->serializer = $this->createMock(SerializerInterface::class);
         $this->transport = new InMemoryTransport();
+        $this->serializeTransport = new InMemoryTransport($this->serializer);
     }
 
     public function testSend()
@@ -38,6 +52,24 @@ public function testSend()
         $this->assertSame([$envelope], $this->transport->getSent());
     }
 
+    public function testSendWithSerialization()
+    {
+        $envelope = new Envelope(new \stdClass());
+        $envelopeDecoded = Envelope::wrap(new DummyMessage('Hello.'));
+        $this->serializer
+            ->method('encode')
+            ->with($this->equalTo($envelope))
+            ->willReturn(['foo' => 'ba'])
+        ;
+        $this->serializer
+            ->method('decode')
+            ->with(['foo' => 'ba'])
+            ->willReturn($envelopeDecoded)
+        ;
+        $this->serializeTransport->send($envelope);
+        $this->assertSame([$envelopeDecoded], $this->serializeTransport->getSent());
+    }
+
     public function testQueue()
     {
         $envelope1 = new Envelope(new \stdClass());
@@ -51,6 +83,24 @@ public function testQueue()
         $this->assertSame([], $this->transport->get());
     }
 
+    public function testQueueWithSerialization()
+    {
+        $envelope = new Envelope(new \stdClass());
+        $envelopeDecoded = Envelope::wrap(new DummyMessage('Hello.'));
+        $this->serializer
+            ->method('encode')
+            ->with($this->equalTo($envelope))
+            ->willReturn(['foo' => 'ba'])
+        ;
+        $this->serializer
+            ->method('decode')
+            ->with(['foo' => 'ba'])
+            ->willReturn($envelopeDecoded)
+        ;
+        $this->serializeTransport->send($envelope);
+        $this->assertSame([$envelopeDecoded], $this->serializeTransport->get());
+    }
+
     public function testAcknowledgeSameMessageWithDifferentStamps()
     {
         $envelope1 = new Envelope(new \stdClass(), [new AnEnvelopeStamp()]);
@@ -71,6 +121,24 @@ public function testAck()
         $this->assertSame([$envelope], $this->transport->getAcknowledged());
     }
 
+    public function testAckWithSerialization()
+    {
+        $envelope = new Envelope(new \stdClass());
+        $envelopeDecoded = Envelope::wrap(new DummyMessage('Hello.'));
+        $this->serializer
+            ->method('encode')
+            ->with($this->equalTo($envelope))
+            ->willReturn(['foo' => 'ba'])
+        ;
+        $this->serializer
+            ->method('decode')
+            ->with(['foo' => 'ba'])
+            ->willReturn($envelopeDecoded)
+        ;
+        $this->serializeTransport->ack($envelope);
+        $this->assertSame([$envelopeDecoded], $this->serializeTransport->getAcknowledged());
+    }
+
     public function testReject()
     {
         $envelope = new Envelope(new \stdClass());
@@ -78,6 +146,24 @@ public function testReject()
         $this->assertSame([$envelope], $this->transport->getRejected());
     }
 
+    public function testRejectWithSerialization()
+    {
+        $envelope = new Envelope(new \stdClass());
+        $envelopeDecoded = Envelope::wrap(new DummyMessage('Hello.'));
+        $this->serializer
+            ->method('encode')
+            ->with($this->equalTo($envelope))
+            ->willReturn(['foo' => 'ba'])
+        ;
+        $this->serializer
+            ->method('decode')
+            ->with(['foo' => 'ba'])
+            ->willReturn($envelopeDecoded)
+        ;
+        $this->serializeTransport->reject($envelope);
+        $this->assertSame([$envelopeDecoded], $this->serializeTransport->getRejected());
+    }
+
     public function testReset()
     {
         $envelope = new Envelope(new \stdClass());
diff --git a/src/Symfony/Component/Messenger/Transport/InMemoryTransport.php b/src/Symfony/Component/Messenger/Transport/InMemoryTransport.php
index 09cbb31a041fd..75a0b445e4759 100644
--- a/src/Symfony/Component/Messenger/Transport/InMemoryTransport.php
+++ b/src/Symfony/Component/Messenger/Transport/InMemoryTransport.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\Messenger\Transport;
 
 use Symfony\Component\Messenger\Envelope;
+use Symfony\Component\Messenger\Transport\Serialization\SerializerInterface;
 use Symfony\Contracts\Service\ResetInterface;
 
 /**
@@ -41,12 +42,22 @@ class InMemoryTransport implements TransportInterface, ResetInterface
      */
     private $queue = [];
 
+    /**
+     * @var SerializerInterface|null
+     */
+    private $serializer;
+
+    public function __construct(SerializerInterface $serializer = null)
+    {
+        $this->serializer = $serializer;
+    }
+
     /**
      * {@inheritdoc}
      */
     public function get(): iterable
     {
-        return array_values($this->queue);
+        return array_values($this->decode($this->queue));
     }
 
     /**
@@ -54,7 +65,7 @@ public function get(): iterable
      */
     public function ack(Envelope $envelope): void
     {
-        $this->acknowledged[] = $envelope;
+        $this->acknowledged[] = $this->encode($envelope);
         $id = spl_object_hash($envelope->getMessage());
         unset($this->queue[$id]);
     }
@@ -64,7 +75,7 @@ public function ack(Envelope $envelope): void
      */
     public function reject(Envelope $envelope): void
     {
-        $this->rejected[] = $envelope;
+        $this->rejected[] = $this->encode($envelope);
         $id = spl_object_hash($envelope->getMessage());
         unset($this->queue[$id]);
     }
@@ -74,9 +85,10 @@ public function reject(Envelope $envelope): void
      */
     public function send(Envelope $envelope): Envelope
     {
-        $this->sent[] = $envelope;
+        $encodedEnvelope = $this->encode($envelope);
+        $this->sent[] = $encodedEnvelope;
         $id = spl_object_hash($envelope->getMessage());
-        $this->queue[$id] = $envelope;
+        $this->queue[$id] = $encodedEnvelope;
 
         return $envelope;
     }
@@ -91,7 +103,7 @@ public function reset()
      */
     public function getAcknowledged(): array
     {
-        return $this->acknowledged;
+        return $this->decode($this->acknowledged);
     }
 
     /**
@@ -99,7 +111,7 @@ public function getAcknowledged(): array
      */
     public function getRejected(): array
     {
-        return $this->rejected;
+        return $this->decode($this->rejected);
     }
 
     /**
@@ -107,6 +119,35 @@ public function getRejected(): array
      */
     public function getSent(): array
     {
-        return $this->sent;
+        return $this->decode($this->sent);
+    }
+
+    /**
+     * @return Envelope|array
+     */
+    private function encode(Envelope $envelope)
+    {
+        if (null === $this->serializer) {
+            return $envelope;
+        }
+
+        return $this->serializer->encode($envelope);
+    }
+
+    /**
+     * @param array<mixed> $messagesEncoded
+     *
+     * @return Envelope[]
+     */
+    private function decode(array $messagesEncoded): array
+    {
+        if (null === $this->serializer) {
+            return $messagesEncoded;
+        }
+
+        return array_map(
+            [$this->serializer, 'decode'],
+            $messagesEncoded
+        );
     }
 }
diff --git a/src/Symfony/Component/Messenger/Transport/InMemoryTransportFactory.php b/src/Symfony/Component/Messenger/Transport/InMemoryTransportFactory.php
index 597107341a977..5da5d5d046945 100644
--- a/src/Symfony/Component/Messenger/Transport/InMemoryTransportFactory.php
+++ b/src/Symfony/Component/Messenger/Transport/InMemoryTransportFactory.php
@@ -26,7 +26,9 @@ class InMemoryTransportFactory implements TransportFactoryInterface, ResetInterf
 
     public function createTransport(string $dsn, array $options, SerializerInterface $serializer): TransportInterface
     {
-        return $this->createdTransports[] = new InMemoryTransport();
+        ['serialize' => $serialize] = $this->parseDsn($dsn);
+
+        return $this->createdTransports[] = new InMemoryTransport($serialize ? $serializer : null);
     }
 
     public function supports(string $dsn, array $options): bool
@@ -40,4 +42,16 @@ public function reset()
             $transport->reset();
         }
     }
+
+    private function parseDsn(string $dsn): array
+    {
+        $query = [];
+        if ($queryAsString = strstr($dsn, '?')) {
+            parse_str(ltrim($queryAsString, '?'), $query);
+        }
+
+        return [
+            'serialize' => filter_var($query['serialize'] ?? false, \FILTER_VALIDATE_BOOLEAN),
+        ];
+    }
 }