diff --git a/userfront/lib/core/services/auth_proxy_service.dart b/userfront/lib/core/services/auth_proxy_service.dart
index d5178f06..8d0f5958 100644
--- a/userfront/lib/core/services/auth_proxy_service.dart
+++ b/userfront/lib/core/services/auth_proxy_service.dart
@@ -13,7 +13,11 @@ class AuthProxyService {
     return dotenv.env[key] ?? fallback;
   }
 
-  static String get _baseUrl => _envOrDefault('BACKEND_URL', 'https://sso.hmac.kr');
+  static String get _baseUrl {
+    final rawUrl = _envOrDefault('BACKEND_URL', 'https://sso.hmac.kr');
+    // 배포 환경에서 $ 기호나 공백이 섞여 들어오는 경우를 방지하기 위해 정제합니다.
+    return rawUrl.replaceAll('$', '').trim().replaceAll(RegExp(r'/$'), '');
+  }
   static bool get _isProd {
     final env = _envOrDefault('APP_ENV', 'dev').toLowerCase();
     return env == 'prod' || env == 'production';