diff --git a/docker-compose.yaml b/docker-compose.yaml
index 5d6e594..fd74fd4 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -64,6 +64,7 @@ services:
       - CMD_DB_URL=postgres://{{ hedgedoc_user }}:{{ hedgedoc_password }}@hedgedoc_db:5432/hedgedoc
       - CMD_DOMAIN=sf-hedgedoc.psi.ch
       - CMD_URL_ADDPORT=false
+      - CMD_PROTOCOL_USESSL=true
     volumes:
       - /opt/webcontent/sf-hedgedoc/uploads:/hedgedoc/public/uploads
     restart: always