diff --git a/src/arbitrade/api/app.py b/src/arbitrade/api/app.py
index b553fb7..9a81d89 100644
--- a/src/arbitrade/api/app.py
+++ b/src/arbitrade/api/app.py
@@ -57,7 +57,7 @@ def _start_feed(app: FastAPI, *, kill_switch_only: bool = False) -> asyncio.Task
         _LOG.warning("no_enabled_pair_symbols_feed_not_started")
         return None
 
-    ws_client: KrakenWsClient = getattr(app.state, "ws_client", None)
+    ws_client: KrakenWsClient | None = getattr(app.state, "ws_client", None)
     if ws_client is None:
         ws_client = KrakenWsClient(settings, alert_notifier=alert_notifier)
         app.state.ws_client = ws_client