diff --git a/src/Config.php b/src/Config.php
index f8e890df..39a3fc9a 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -65,7 +65,8 @@ class Config
         'minimum_level',
         'verbose',
         'verbose_logger',
-        'raise_on_error'
+        'raise_on_error',
+        'transformer',
     );
     
     private $accessToken;
diff --git a/tests/DefaultsTest.php b/tests/DefaultsTest.php
index 484360a1..d61e3936 100644
--- a/tests/DefaultsTest.php
+++ b/tests/DefaultsTest.php
@@ -271,14 +271,15 @@ public function testDefaultsForConfigOptions()
     {
         foreach (\Rollbar\Config::listOptions() as $option) {
             if ($option == 'access_token' ||
+                $option == 'include_raw_request_body' ||
+                $option == 'log_payload_logger' ||
                 $option == 'logger' ||
                 $option == 'person' ||
                 $option == 'person_fn' ||
-                $option == 'scrub_whitelist' ||
                 $option == 'proxy' ||
-                $option == 'include_raw_request_body' ||
-                $option == 'verbose_logger' ||
-                $option == 'log_payload_logger') {
+                $option == 'scrub_whitelist' ||
+                $option == 'transformer' ||
+                $option == 'verbose_logger') {
                 continue;
             } elseif ($option == 'base_api_url') {
                 $option = 'endpoint';