···11-diff --git a/samcli/local/services/base_local_service.py b/samcli/local/services/base_local_service.py
22-index 7b1ab95895d1..76812f02e00a 100644
33---- a/samcli/local/services/base_local_service.py
44-+++ b/samcli/local/services/base_local_service.py
55-@@ -56,9 +56,11 @@ class BaseLocalService:
66-77- LOG.debug("Localhost server is starting up. Multi-threading = %s", multi_threaded)
88-99-- # This environ signifies we are running a main function for Flask. This is true, since we are using it within
1010-- # our cli and not on a production server.
1111-- os.environ["WERKZEUG_RUN_MAIN"] = "true"
1212-+ # Suppress flask dev server output in a forward-compatible way
1313-+ # Source: https://github.com/cs01/gdbgui/issues/425#issuecomment-1119836533
1414-+ import flask.cli
1515-+
1616-+ flask.cli.show_server_banner = lambda *args: None
1717-1818- self._app.run(threaded=multi_threaded, host=self.host, port=self.port)
1919-