diff --git a/Client/Client.php b/Client/Client.php
index a15281f..d1a6e56 100644
--- a/Client/Client.php
+++ b/Client/Client.php
@@ -7,7 +7,7 @@
 /**
  * @author Pierre Rolland <roll.pierre@gmail.com>
  */
-class Client
+class Client implements ClientInterface
 {
     /** @var ConnectionInterface */
     protected $connection;
diff --git a/Client/ClientStack.php b/Client/ClientStack.php
index 7477f1e..988544b 100644
--- a/Client/ClientStack.php
+++ b/Client/ClientStack.php
@@ -28,6 +28,11 @@ public function removeClient(ConnectionInterface $connection)
         unset($this->clients[$this->getClientIndex($connection)]);
     }
 
+    public function getClients(): array
+    {
+        return $this->clients;
+    }
+
     private function getClientIndex(ConnectionInterface $connection): int
     {
         foreach ($this->clients as $i => $c) {
diff --git a/Websocket.php b/Websocket.php
index b7607aa..a98586e 100644
--- a/Websocket.php
+++ b/Websocket.php
@@ -30,7 +30,7 @@ public function __construct(HandlerRegistry $handlerRegistry, string $clientClas
 
     public function onOpen(ConnectionInterface $conn)
     {
-        $this->clientStack->addClient(new ${$this->clientClass}($conn));
+        $this->clientStack->addClient(new $this->clientClass($conn));
     }
 
     public function onMessage(ConnectionInterface $from, $msg)