diff --git a/src/ShipmentData.php b/src/ShipmentData.php
index eaa2c71..bc25440 100644
--- a/src/ShipmentData.php
+++ b/src/ShipmentData.php
@@ -196,10 +196,10 @@ public static function fromJson(array $json): self
     {
         /** @var ShipmentData $result */
         $result = self::create();
-        $result->orderIncrement = $json['order_increment_id'] ?? null;
+        $result->orderIncrement = $json['orderIncrementId'] ?? null;
         $result->arguments = Argument::fromJson($json['arguments'] ?? []);
         $result->notify = $json['notify'] ?? false;
-        $result->appendComment = $json['append_comment'] ?? false;
+        $result->appendComment = $json['appendComment'] ?? false;
         $result->comments = CommentCollection::fromJson($json['comments'] ?? []);
         $result->items = ItemCollection::fromJson($json['items']);
         $result->packages = PackageCollection::fromJson($json['packages'] ?? []);
@@ -212,7 +212,7 @@ public function toJson() : array
         $json = [];
 
         if ($this->getOrderIncrement()) {
-            $json['order_increment_id'] = $this->getOrderIncrement();
+            $json['orderIncrementId'] = $this->getOrderIncrement();
         }
         if (!$this->getTracks()->isEmpty()) {
             $json['tracks'] = $this->getTracks()->toJson();
@@ -233,7 +233,7 @@ public function toJson() : array
             $json['notify'] = $this->getNotify();
         }
         if ($this->getAppendComment()) {
-            $json['append_comment'] = $this->getAppendComment();
+            $json['appendComment'] = $this->getAppendComment();
         }
 
         return $json;
diff --git a/test/unit/ShipmentDataTest.php b/test/unit/ShipmentDataTest.php
index 7b4c06e..ca33107 100644
--- a/test/unit/ShipmentDataTest.php
+++ b/test/unit/ShipmentDataTest.php
@@ -46,7 +46,7 @@ public function testEquals()
     private function getShipmentsJson()
     {
         return [
-            "order_increment_id" => "100",
+            "orderIncrementId" => "100",
             "arguments" => Argument::create()->withExtensionAttributes(
                 ExtensionAttributeSet::of([
                     ExtensionAttribute::of('code1', 'value1'),
@@ -54,7 +54,7 @@ private function getShipmentsJson()
                 ])
             )->toJson(),
             "notify" => true,
-            "append_comment" => true,
+            "appendComment" => true,
             "comments" => CommentCollection::create()->with(Comment::create()
                 ->withComment("test comment")
                 ->withIsCustomerNotified(1)