diff --git a/index.html b/index.html
index 0f9c9e7..63cd85b 100644
--- a/index.html
+++ b/index.html
@@ -716,7 +716,70 @@ function startDepositWatch(chain, id) {
   pollDeposit();
 }
 
-document.getElementById('check').addEventListener('click', () => document.getElementById('submit').click());
+// "Check server" is read-only: it looks the URL up in the list (GET /datalist) and
+// shows the server's expiry and balance from /weinfodata. It never POSTs to /data,
+// so checking a URL that is not listed creates nothing.
+function normalizeUrl(u) {
+  u = u.trim();
+  if (!u) return '';
+  if (!u.startsWith('http://') && !u.startsWith('https://')) u = 'https://' + u;
+  return u.replace(/\/+$/, '');
+}
+function hidePaymentRows() {
+  document.getElementById('iv-min').parentElement.style.display = 'none';
+  document.getElementById('iv-addr').parentElement.style.display = 'none';
+  document.getElementById('qrcode').style.display = 'none';
+  document.getElementById('share-btn').style.display = 'none';
+}
+document.getElementById('check').addEventListener('click', async () => {
+  stopDepositWatch();
+  const urlInput = document.getElementById('url');
+  const url = normalizeUrl(urlInput.value);
+  if (!url) return;
+  urlInput.value = url;
+  const chain = getChain();
+  const status = document.getElementById('iv-status');
+  const inv = document.getElementById('invoice');
+  inv.classList.remove('show');
+  document.getElementById('terms-box').classList.remove('show');
+  status.className = '';
+  status.textContent = 'Checking…';
+  try {
+    const listResp = await fetch(`/datalist/${chain}?page=0&limit=100`);
+    if (!listResp.ok) throw new Error(`HTTP ${listResp.status}`);
+    const list = await listResp.json();
+    const idx = list.findIndex(d => normalizeUrl(d.url || '').toLowerCase() === url.toLowerCase());
+    if (idx < 0) {
+      status.className = 'err-line';
+      status.textContent = `Not in the ${chain} list: no server with this exact URL. To list it, press "Add server".`;
+      return;
+    }
+    const d = list[idx];
+    const infoResp = await fetch(`/weinfodata/${chain}/${d.id}`);
+    const info = infoResp.ok ? await infoResp.json() : {};
+    const expiry = (info.expiry_date || '').slice(0, 10) || '—';   // '2027-07-16 00:00:00' -> the date
+    const bal = info.balance != null ? fmt(info.balance) : null;
+    const unc = info.unconfirmed_balance != null ? fmt(info.unconfirmed_balance) : null;
+    document.getElementById('iv-chain').textContent = info.chain || chain;
+    document.getElementById('iv-balance').textContent = bal ? (unc ? bal + ' (' + unc + ')' : bal) : '—';
+    document.getElementById('iv-donations').textContent = info.donation != null ? fmt(info.donation) : '—';
+    document.getElementById('iv-contact').textContent = '—';
+    document.getElementById('iv-url').textContent = d.url;
+    const weinfoEl = document.getElementById('iv-weinfo');
+    weinfoEl.href = `/weinfo/${chain}/${d.id}`;
+    weinfoEl.textContent = 'View page';
+    document.getElementById('iv-nextdep').textContent = expiry;
+    document.getElementById('iv-nextdep-row').style.display = 'flex';
+    hidePaymentRows();
+    status.className = 'ok-line';
+    status.textContent = `Server is listed (#${idx + 1} of ${list.length}). Expiry: ${expiry}. Renewal opens 6 months before.`;
+    inv.classList.add('show');
+    inv.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
+  } catch (err) {
+    status.className = 'err-line';
+    status.textContent = 'Could not check the list right now. Please try again in a moment.';
+  }
+});
 document.getElementById('submit').addEventListener('click', async () => {
   stopDepositWatch();
   const urlInput = document.getElementById('url');