diff --git a/PSWebServiceLibrary.php b/PSWebServiceLibrary.php
index 82db929..951678a 100644
--- a/PSWebServiceLibrary.php
+++ b/PSWebServiceLibrary.php
@@ -173,6 +173,8 @@ protected function executeRequest($url, $curl_params = array())
     {
         $defaultParams = $this->getCurlDefaultParams();
 
+		$url .= '&ws_key=' . $this->key;
+
         $session = curl_init($url);
 
         $curl_options = array();