diff --git a/compose.yml b/compose.yml
index c360bf2..c630331 100644
--- a/compose.yml
+++ b/compose.yml
@@ -30,8 +30,8 @@ services:
       POSTGRES_USER: ${POSTGRES_USER:-user}
       POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-password}
       POSTGRES_DB: ${POSTGRES_DB:-datashield}
-    ports:
-      - "5432:5432"
+    # No host port publish: app reaches db over the internal compose network
+    # (db:5432). Avoids clashing with a Postgres already bound to host 5432.
     volumes:
       - datashield-db-data:/var/lib/postgresql/data
     healthcheck: