diff --git a/index.html b/index.html
index f81ad00..cf3c9d6 100644
--- a/index.html
+++ b/index.html
@@ -494,7 +494,7 @@
         domain: { input: document.getElementById('domain'),  wrapper: document.getElementById('domainWrapper'), error: document.getElementById('domainError') }
       };
 
-      const API_URL = 'http://192.168.1.121:8080';
+      const API_URL = ''; // relative — same origin
 
       function validateEmail(v) {
         return /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(v.trim());