diff --git a/vorschau/js/app.js b/vorschau/js/app.js
index 3078ec3..5d31d50 100644
--- a/vorschau/js/app.js
+++ b/vorschau/js/app.js
@@ -351,21 +351,36 @@ function mdToHtml(md) {
         }
     });
 
-    // Form submit -> mailto fallback (no backend yet)
+    // Form submit -> server-side SMTP
     window.submitContact = function (e) {
         e.preventDefault();
-        var name = document.getElementById('cf-name').value;
-        var org = document.getElementById('cf-org').value;
-        var email = document.getElementById('cf-email').value;
-        var msg = document.getElementById('cf-message').value;
+        var btn = e.target.querySelector('button[type="submit"]');
+        if (btn) { btn.disabled = true; btn.textContent = 'Wird gesendet...'; }
 
-        var subject = 'Anfrage von ' + name + (org ? ' (' + org + ')' : '');
-        var body = 'Name: ' + name + '\nOrganisation: ' + (org || '-') + '\nE-Mail: ' + email + '\n\nNachricht:\n' + msg;
-
-        window.location.href = 'mailto:info@aegis-sight.de?subject=' + encodeURIComponent(subject) + '&body=' + encodeURIComponent(body);
-
-        document.getElementById('contact-form').style.display = 'none';
-        document.getElementById('form-success').style.display = 'block';
+        fetch('/api/contact', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({
+                name: document.getElementById('cf-name').value,
+                organisation: document.getElementById('cf-org').value,
+                email: document.getElementById('cf-email').value,
+                message: document.getElementById('cf-message').value
+            })
+        })
+        .then(function (r) { return r.json().then(function (d) { return { ok: r.ok, data: d }; }); })
+        .then(function (res) {
+            if (res.ok) {
+                document.getElementById('contact-form').style.display = 'none';
+                document.getElementById('form-success').style.display = 'block';
+            } else {
+                alert(res.data.error || 'Fehler beim Senden');
+                if (btn) { btn.disabled = false; btn.textContent = 'Nachricht senden'; }
+            }
+        })
+        .catch(function () {
+            alert('Verbindungsfehler. Bitte versuchen Sie es erneut.');
+            if (btn) { btn.disabled = false; btn.textContent = 'Nachricht senden'; }
+        });
         return false;
     };