diff --git a/src/Wuunder/Api/Config/Config.php b/src/Wuunder/Api/Config/Config.php
index 3072a55..fa2961b 100644
--- a/src/Wuunder/Api/Config/Config.php
+++ b/src/Wuunder/Api/Config/Config.php
@@ -33,10 +33,8 @@ public function __call($method, $args)
 
     /**
     * Adds together default and user input items
-    *
-    * @return array A full list of all the items that are set by user and default
     */
-    public function jsonSerialize()
+    public function jsonSerialize(): mixed
     {
         return array_merge($this->defaultFields, $this->setFields);
     }
diff --git a/src/Wuunder/Model/Model.php b/src/Wuunder/Model/Model.php
index 9605c4f..3347b59 100644
--- a/src/Wuunder/Model/Model.php
+++ b/src/Wuunder/Model/Model.php
@@ -117,7 +117,7 @@ private function _underscore($name)
         return $result;
     }
 
-    public function jsonSerialize()
+    public function jsonSerialize(): mixed
     {
         return $this->data;
     }