diff --git a/php/config.yaml b/php/config.yaml
index 5128ddd119b..bb126e82054 100644
--- a/php/config.yaml
+++ b/php/config.yaml
@@ -25,6 +25,8 @@ language:
         - sockets
       command: php public/index.php start
     road-runner:
+      extensions:
+        - protobuf
       files:
         - .rr.yaml
       bootstrap: