diff --git a/src/Symfony/Component/Serializer/Mapping/AttributeMetadataInterface.php b/src/Symfony/Component/Serializer/Mapping/AttributeMetadataInterface.php
index 0701a58b56257..6bb30274e3428 100644
--- a/src/Symfony/Component/Serializer/Mapping/AttributeMetadataInterface.php
+++ b/src/Symfony/Component/Serializer/Mapping/AttributeMetadataInterface.php
@@ -16,6 +16,8 @@
  *
  * Primarily, the metadata stores serialization groups.
  *
+ * @internal
+ *
  * @author Kévin Dunglas <dunglas@gmail.com>
  */
 interface AttributeMetadataInterface
diff --git a/src/Symfony/Component/Serializer/Mapping/ClassMetadataInterface.php b/src/Symfony/Component/Serializer/Mapping/ClassMetadataInterface.php
index 095587d8961b3..5889f0da11886 100644
--- a/src/Symfony/Component/Serializer/Mapping/ClassMetadataInterface.php
+++ b/src/Symfony/Component/Serializer/Mapping/ClassMetadataInterface.php
@@ -18,6 +18,8 @@
  *
  * There may only exist one metadata for each attribute according to its name.
  *
+ * @internal
+ *
  * @author Kévin Dunglas <dunglas@gmail.com>
  */
 interface ClassMetadataInterface