diff --git a/apps/web/src/views/checkout.ejs b/apps/web/src/views/checkout.ejs
index 2ce320d..ebac70a 100644
--- a/apps/web/src/views/checkout.ejs
+++ b/apps/web/src/views/checkout.ejs
@@ -216,7 +216,7 @@
         <span class="w-1.5 h-1.5 rounded-full <%= inv.status === 'underpaid' ? 'bg-yellow-500' : 'bg-blue-500' %> animate-pulse"></span>
         <span class="text-xs <%= inv.status === 'underpaid' ? 'text-yellow-400' : 'text-gray-400' %>"><%= inv.status === 'underpaid' ? 'Underpaid, send the rest' : 'Waiting for payment' %></span>
       </div>
-      <span id="timer" class="text-xs text-gray-500 font-mono" data-expires="<%= expiresAt.toISOString() %>"><%= mins %>:<%= String(secs).padStart(2, '0') %></span>
+      <span id="timer" class="text-xs text-gray-500 font-mono" data-left="<%= remainingSec %>"><%= mins %>:<%= String(secs).padStart(2, '0') %></span>
     </div>
 
     <% } else if (inv.status === 'confirming') { %>
@@ -268,7 +268,7 @@
     // Countdown timer
     const timerEl = document.getElementById('timer');
     if (timerEl) {
-      let left = <%= remainingSec %>;
+      let left = parseInt(timerEl.dataset.left);
       setInterval(() => {
         left = Math.max(0, left - 1);
         timerEl.textContent = Math.floor(left / 60) + ':' + String(left % 60).padStart(2, '0');