diff --git a/include/motis/config.h b/include/motis/config.h
index 97ac5e2d2..d6098914e 100644
--- a/include/motis/config.h
+++ b/include/motis/config.h
@@ -115,7 +115,7 @@ struct config {
     unsigned update_interval_{60};
     unsigned http_timeout_{10};
     unsigned cache_size_{50};
-    std::optional<std::string> proxy_;
+    std::optional<std::string> proxy_{};
   };
   std::optional<gbfs> gbfs_{};