diff --git a/composer.json b/composer.json
index f63acff..81774b5 100644
--- a/composer.json
+++ b/composer.json
@@ -9,6 +9,13 @@
     "license": [
         "MIT"
     ],
+    "authors": [
+        {
+            "name": "SapientPro",
+            "email": "info@sapient.pro",
+            "homepage": "https://sapient.pro/"
+        }
+    ],
     "require": {
         "php": "^8.1",
         "ext-mbstring": "*",
diff --git a/src/Client/Serializer.php b/src/Client/Serializer.php
index 2d92af8..173fca4 100644
--- a/src/Client/Serializer.php
+++ b/src/Client/Serializer.php
@@ -7,6 +7,7 @@
 use Symfony\Component\PropertyInfo\Extractor\ReflectionExtractor;
 use Symfony\Component\PropertyInfo\PropertyInfoExtractor;
 use Symfony\Component\Serializer\Encoder\JsonEncoder;
+use Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer;
 use Symfony\Component\Serializer\Normalizer\ArrayDenormalizer;
 use Symfony\Component\Serializer\Normalizer\BackedEnumNormalizer;
 use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
@@ -31,12 +32,14 @@ public function __construct()
 
     public function deserialize(string $json, string $class): ?EbayModelInterface
     {
-        return $this->serializer->deserialize($json, $class, 'json');
+        return $this->serializer->deserialize($json, $class, JsonEncoder::FORMAT);
     }
 
     public function serialize(EbayModelInterface $class): string
     {
-        return $this->serializer->serialize($class, JsonEncoder::FORMAT);
+        return $this->serializer->serialize($class, JsonEncoder::FORMAT, [
+            AbstractObjectNormalizer::SKIP_NULL_VALUES => true
+        ]);
     }
 
     public function denormalize(array $data, string $type): ?EbayModelInterface