diff --git a/site/metamask.html b/site/metamask.html
index f4458f7ba..faf9aea6c 100644
--- a/site/metamask.html
+++ b/site/metamask.html
@@ -261,7 +261,7 @@ ol{margin:0 0 14px;padding-left:22px}li{margin-bottom:6px}
     <p>The public RPC answers at rpc.devnet.igneum.network; the Igneum Miner app also runs a full node on your machine and serves the Ethereum RPC on it, and the wallet can point at either. The devnet is a developer network: it resets without notice and its coins have no value.</p>
     <dl>
       <dt>Network name</dt><dd>Igneum Devnet 3</dd>
-      <dt>Chain id</dt><dd>4464 (0x1170) on Devnet 3, since its class v5 floor at DAA 68,400 on 8 October 2026 (4463 before it)</dd>
+      <dt>Chain id</dt><dd id="dev-chain">4464 (0x1170) on Devnet 3, since its class v5 floor at DAA 68,400 on 8 October 2026 (4463 before it)</dd>
       <dt>RPC URL</dt><dd>https://rpc.devnet.igneum.network (a node you run serves http://127.0.0.1:26790)</dd>
       <dt>Symbol</dt><dd>IGN</dd>
       <dt>Decimals</dt><dd>18</dd>
@@ -378,6 +378,15 @@ ol{margin:0 0 14px;padding-left:22px}li{margin-bottom:6px}
     devnet:  { chainId: '0x1170', chainName: 'Igneum Devnet 3', nativeCurrency: { name: 'Igneum', symbol: 'IGN', decimals: 18 }, rpcUrls: ['https://rpc.devnet.igneum.network'], blockExplorerUrls: ['https://igneum.network/explorer'] }
   };
   function status(name, text) { var el = document.querySelector('[data-status="' + name + '"]'); if (el) el.textContent = text; }
+  // Devnet 3's chain id moves at every class floor (4463 to 4464 at the class v5 floor, 8 October 2026), so the entry's id and
+  // the card's figure are read from the public RPC at load; the pinned 0x1170 is the answer when the RPC does not reply.
+  fetch('https://rpc.devnet.igneum.network', { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify({ jsonrpc: '2.0', id: 1, method: 'eth_chainId', params: [] }) })
+    .then(function (r) { return r.json(); })
+    .then(function (d) {
+      var hex = d && typeof d.result === 'string' && /^0x[0-9a-f]+$/i.test(d.result) ? d.result.toLowerCase() : null; if (!hex) return;
+      CHAINS.devnet.chainId = hex;
+      var cell = document.getElementById('dev-chain'); if (cell) cell.textContent = parseInt(hex, 16) + ' (' + hex + ') on Devnet 3, read from the public RPC now; 4463 before its class v5 floor at DAA 68,400 on 8 October 2026';
+    }).catch(function () {});
   Array.prototype.forEach.call(document.querySelectorAll('[data-add]'), function (btn) {
     btn.addEventListener('click', function () {
       var name = btn.getAttribute('data-add'); var chain = CHAINS[name];