diff --git a/frontend/src/api/client.ts b/frontend/src/api/client.ts
index aa32d68..f0224a0 100644
--- a/frontend/src/api/client.ts
+++ b/frontend/src/api/client.ts
@@ -3,9 +3,9 @@
  * Base URLs are configurable via env vars (VITE_*).
  */
 
-const QUERY_API_BASE = import.meta.env.VITE_QUERY_API_URL ?? '';
-const SYMBOL_REGISTRY_BASE = import.meta.env.VITE_SYMBOL_REGISTRY_URL ?? '/registry';
-const RISK_ENGINE_BASE = import.meta.env.VITE_RISK_ENGINE_URL ?? '/risk';
+const QUERY_API_BASE = import.meta.env.VITE_QUERY_API_URL || '';
+const SYMBOL_REGISTRY_BASE = import.meta.env.VITE_SYMBOL_REGISTRY_URL || '/registry';
+const RISK_ENGINE_BASE = import.meta.env.VITE_RISK_ENGINE_URL || '/risk';
 
 export type ApiBase = 'query' | 'registry' | 'risk';