diff --git a/appengine/mailjet/src/main/webapp/WEB-INF/appengine-web.xml b/appengine/mailjet/src/main/webapp/WEB-INF/appengine-web.xml
index 5e127cc369f..653950db1c9 100644
--- a/appengine/mailjet/src/main/webapp/WEB-INF/appengine-web.xml
+++ b/appengine/mailjet/src/main/webapp/WEB-INF/appengine-web.xml
@@ -17,8 +17,10 @@
   <application>YOUR-PROJECT-ID</application>
   <version>YOUR-VERSION-ID</version>
   <threadsafe>true</threadsafe>
+// [START env_variables]
   <env-variables>
     <env-var name="MAILJET_API_KEY" value="YOUR-MAILJET-API-KEY" />
     <env-var name="MAILJET_SECRET_KEY" value="YOUR-MAILJET-SECRET-KEY" />
   </env-variables>
+// [END env_variables]
 </appengine-web-app>