diff --git a/src/backend/src/ExtensionService.js b/src/backend/src/ExtensionService.js
index 2c9cf1f9..23409888 100644
--- a/src/backend/src/ExtensionService.js
+++ b/src/backend/src/ExtensionService.js
@@ -63,6 +63,7 @@ class ExtensionServiceState extends AdvancedBase {
             mw,
             route: path,
             handler: handler,
+            ...(options.subdomain ? { subdomain: options.subdomain } : {}),
         });
     
         this.endpoints_.push(endpoint);