diff --git a/gitops/stack.yml b/gitops/stack.yml
index 5b98b16..e8dad90 100644
--- a/gitops/stack.yml
+++ b/gitops/stack.yml
@@ -23,7 +23,7 @@ services:
     expose:
       - "80"
     environment:
-      DATABASE_URL: postgresql://materialschein:${POSTGRES_PASSWORD}@tools_bergvolt_at-db:5432/materialschein
+      DATABASE_URL: postgresql://materialschein:${POSTGRES_PASSWORD}@materialschein-db:5432/materialschein
       MSAL_CLIENT_ID: b1cd974c-77ce-4d93-b6e8-00e41a31adc8
       MSAL_TENANT_ID: d9adeaaf-853b-4c4e-a822-8f1bedbb84f6
       PORT: "80"
@@ -38,8 +38,11 @@ services:
     image: postgres:16-alpine
     container_name: tools_bergvolt_at-db
     restart: unless-stopped
+    # Eindeutiger DNS-Alias statt generischem Namen — DATABASE_URL zeigt auf
+    # materialschein-db, unabhängig von container_name/Service-Namen.
     networks:
-      - internal
+      internal:
+        aliases: [materialschein-db]
     environment:
       POSTGRES_USER: materialschein
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}