diff --git a/bemani/api/app.py b/bemani/api/app.py
index 1286d1e..fd073bd 100644
--- a/bemani/api/app.py
+++ b/bemani/api/app.py
@@ -53,6 +53,7 @@ def after_request(response: Response) -> Response:
     response.cache_control.no_cache = True
     response.cache_control.must_revalidate = True
     response.cache_control.private = True
+    return response
 
 
 @app.teardown_request