diff --git a/README.md b/README.md
index b588c29..f7365b7 100644
--- a/README.md
+++ b/README.md
@@ -109,6 +109,7 @@ services:
       - SYMFONY__ENV__MAILER_USER=~
       - SYMFONY__ENV__MAILER_PASSWORD=~
       - SYMFONY__ENV__FROM_EMAIL=wallabag@example.com
+      - SYMFONY__ENV__DOMAIN_NAME=your-wallabag-url-instance.com
     ports:
       - "80"
     volumes: