diff --git a/lib/models/requests/oauth/register_client.dart b/lib/models/requests/oauth/register_client.dart
index c4ef68f..cf4f9e0 100644
--- a/lib/models/requests/oauth/register_client.dart
+++ b/lib/models/requests/oauth/register_client.dart
@@ -16,6 +16,9 @@ abstract class OAuthRegisterClientRequest with _$OAuthRegisterClientRequest {
     IList<GrantType>? grantTypes,
     IList<Uri>? redirectUris,
     IList<ResponseType>? responseTypes,
+
+    @Default(AuthMethod.none)
+    @JsonKey(name: "token_endpoint_auth_method")
     AuthMethod? authMethod,
   }) = _OAuthRegisterClientRequest;