diff --git a/.env.docker.production.example b/.env.docker.production.example
index 103d100..2430608 100644
--- a/.env.docker.production.example
+++ b/.env.docker.production.example
@@ -67,6 +67,10 @@ JWT_SECRET=eb9ab3eb5d6648bdb82cbef29afde498c58f089829a037dfea6cb5e98ef2aae0
 JWT_EXPIRY=8h
 RENTER_JWT_EXPIRY=7d
 NODE_ENV=production
+# Shared parent-domain cookie so sessions work across rentaldrivego.ma and
+# api.rentaldrivego.ma (the admin/dashboard apps call the API cross-origin).
+# Must start with a leading dot.
+SESSION_COOKIE_DOMAIN=.rentaldrivego.ma
 
 
 # ── Email ─────────────────────────────────────────────────────────────────────