diff --git a/src/Helpers/DataAttributesHelper.php b/src/Helpers/DataAttributesHelper.php
index 68c0ac8..d76b658 100644
--- a/src/Helpers/DataAttributesHelper.php
+++ b/src/Helpers/DataAttributesHelper.php
@@ -72,17 +72,22 @@ class DataAttributesHelper
     /**
      * @param \NilPortugues\Api\Mapping\Mapping[] $mappings
      * @param array                               $array
+     * @param string                              $attributesCase
      *
      * @return array
      */
-    public static function setResponseDataAttributes(array &$mappings, array &$array)
+    public static function setResponseDataAttributes(array &$mappings, array &$array, string $attributesCase)
     {
         $attributes = [];
         $type = $array[Serializer::CLASS_IDENTIFIER_KEY];
         $idProperties = RecursiveFormatterHelper::getIdProperties($mappings, $type);
 
         foreach ($array as $propertyName => $value) {
-            $keyName = self::transformToValidMemberName(RecursiveFormatterHelper::camelCaseToUnderscore($propertyName));
+            if ($attributesCase == 'snake_case') {
+                $propertyName = RecursiveFormatterHelper::camelCaseToUnderscore($propertyName);
+            }
+
+            $keyName = self::transformToValidMemberName($propertyName);
 
             if (\in_array($propertyName, $idProperties, true)) {
                 self::addIdPropertiesInAttribute($mappings, $type, $keyName, $value, $attributes);
@@ -93,7 +98,11 @@ public static function setResponseDataAttributes(array &$mappings, array &$array
                 && empty($mappings[$value[Serializer::CLASS_IDENTIFIER_KEY]])
             ) {
                 $copy = $value;
-                self::recursiveSetKeysToUnderScore($copy);
+
+                if ($attributesCase == 'snake_case') {
+                    self::recursiveSetKeysToUnderScore($copy);
+                }
+                
                 $attributes[$keyName] = $copy;
                 continue;
             }
diff --git a/src/Helpers/DataLinksHelper.php b/src/Helpers/DataLinksHelper.php
index 1228ea0..8c10cdd 100644
--- a/src/Helpers/DataLinksHelper.php
+++ b/src/Helpers/DataLinksHelper.php
@@ -80,7 +80,7 @@ public static function setResponseDataLinks(array &$mappings, array &$value)
      *
      * @return array
      */
-    public static function setResponseDataRelationship(array &$mappings, array &$array, array $parent)
+    public static function setResponseDataRelationship(array &$mappings, array &$array, array $parent, string $attributesCase)
     {
         $data = [JsonApiTransformer::RELATIONSHIPS_KEY => []];
 
@@ -109,7 +109,10 @@ public static function setResponseDataRelationship(array &$mappings, array &$arr
                                     $href = \str_replace($idProperties, $idValues, $selfLink);
                                     if ($selfLink != $href) {
                                         $propertyNameKey = DataAttributesHelper::transformToValidMemberName($propertyName);
-                                        $propertyNameKey = self::camelCaseToUnderscore($propertyNameKey);
+
+                                        if ($attributesCase == 'snake_case') {
+                                            $propertyNameKey = RecursiveFormatterHelper::camelCaseToUnderscore($propertyNameKey);
+                                        }
 
                                         $newData[JsonApiTransformer::RELATIONSHIPS_KEY][$propertyNameKey][JsonApiTransformer::LINKS_KEY][JsonApiTransformer::SELF_LINK][JsonApiTransformer::LINKS_HREF] = $href;
                                     }
@@ -119,7 +122,9 @@ public static function setResponseDataRelationship(array &$mappings, array &$arr
 
                         if (!empty($newData[JsonApiTransformer::RELATIONSHIPS_KEY][$propertyName])) {
                             $propertyNameKey = DataAttributesHelper::transformToValidMemberName($propertyName);
-                            $propertyNameKey = self::camelCaseToUnderscore($propertyNameKey);
+                            if ($attributesCase == 'snake_case') {
+                                $propertyNameKey = RecursiveFormatterHelper::camelCaseToUnderscore($propertyNameKey);
+                            }
 
                             if (!empty($d[Serializer::CLASS_IDENTIFIER_KEY])) {
                                 $type = $d[Serializer::CLASS_IDENTIFIER_KEY];
diff --git a/src/JsonApiTransformer.php b/src/JsonApiTransformer.php
index 03ddffe..850284a 100644
--- a/src/JsonApiTransformer.php
+++ b/src/JsonApiTransformer.php
@@ -96,9 +96,9 @@ protected function serialization(array &$value)
         $data = [
             self::DATA_KEY => \array_merge(
                 PropertyHelper::setResponseDataTypeAndId($this->mappings, $value),
-                DataAttributesHelper::setResponseDataAttributes($this->mappings, $value),
+                DataAttributesHelper::setResponseDataAttributes($this->mappings, $value, $this->attributesCase),
                 DataLinksHelper::setResponseDataLinks($this->mappings, $value),
-                DataLinksHelper::setResponseDataRelationship($this->mappings, $value, $value)
+                DataLinksHelper::setResponseDataRelationship($this->mappings, $value, $value, $this->attributesCase)
             ),
         ];