diff --git a/VERSION b/VERSION
index 448a0fa..09e9157 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.3.4
\ No newline at end of file
+0.3.5
\ No newline at end of file
diff --git a/public/index.html b/public/index.html
index dc6d123..dad61b5 100644
--- a/public/index.html
+++ b/public/index.html
@@ -188,9 +188,15 @@
 
       async function loadBalance() {
         try {
-          const res = await fetch(basePath + "/balance");
+          const config = window.SMS_CONFIG || {};
+          const params = new URLSearchParams({ login: config.login, psw: config.psw });
+          const res = await fetch(basePath + "/balance?" + params);
           const data = await res.json();
-          document.getElementById("balance").textContent = data.balance;
+          if (data.error) {
+            document.getElementById("balance").textContent = "Auth Error";
+          } else {
+            document.getElementById("balance").textContent = data.balance;
+          }
         } catch (err) {
           document.getElementById("balance").textContent = "Error";
         }
diff --git a/server.js b/server.js
index ce72e2b..bc4caa1 100644
--- a/server.js
+++ b/server.js
@@ -103,9 +103,16 @@ router.get("/balance", (req, res) => {
 // Serve static files
 router.use(express.static(path.join(__dirname, "public")));
 
-// GET / - serve main page
+// GET / - serve main page with injected credentials
 router.get("/", (req, res) => {
-  res.sendFile(path.join(__dirname, "public", "index.html"));
+  const indexPath = path.join(__dirname, "public", "index.html");
+  let html = fs.readFileSync(indexPath, "utf8");
+
+  // Inject credentials for frontend
+  const configScript = `<script>window.SMS_CONFIG = { login: "${AUTH_LOGIN || ""}", psw: "${AUTH_PASSWORD || ""}" };</script>`;
+  html = html.replace("</head>", configScript + "</head>");
+
+  res.send(html);
 });
 
 // Mount router at BASE_PATH