diff --git a/public/gamejam.html b/public/gamejam.html
index 265edaf..5335e8c 100644
--- a/public/gamejam.html
+++ b/public/gamejam.html
@@ -632,6 +632,10 @@ setInterval(renderHud, 1000);
      POST {API_BASE}/upload          -> FormData { teilnehmer, game, file } */
 const API_BASE = "/api/gamejam";
 
+/* Hart-Deadline für Einreichungen — danach ist die UI gesperrt und der Server lehnt ab. */
+const UPLOAD_DEADLINE = new Date("2026-05-27T22:00:00+02:00");
+function uploadsOpen() { return Date.now() < UPLOAD_DEADLINE.getTime(); }
+
 const teamEl = document.getElementById("teamName");
 const gameEl = document.getElementById("gameName");
 const dz = document.getElementById("dropzone");
@@ -667,11 +671,23 @@ function pickFile(f) {
   refreshUploadBtn();
 }
 function refreshUploadBtn() {
-  uploadBtn.disabled = !(API_BASE && chosenFile && teamEl.value.trim() && gameEl.value.trim());
+  uploadBtn.disabled = !(uploadsOpen() && API_BASE && chosenFile && teamEl.value.trim() && gameEl.value.trim());
 }
 teamEl.addEventListener("input", refreshUploadBtn);
 gameEl.addEventListener("input", refreshUploadBtn);
 
+/* Wenn die Deadline überschritten ist: Formular sperren und Hinweis anzeigen. */
+if (!uploadsOpen()) {
+  teamEl.disabled = true;
+  gameEl.disabled = true;
+  fileInput.disabled = true;
+  dz.style.pointerEvents = "none";
+  dz.style.opacity = "0.5";
+  uploadBtn.textContent = "Einreichungen geschlossen";
+  uploadBtn.disabled = true;
+  setStatus("Die Einreichungsfrist ist am 27.05.2026 um 22:00 Uhr abgelaufen.", "err");
+}
+
 uploadBtn.addEventListener("click", async () => {
   if (!API_BASE || !chosenFile) return;
   uploadBtn.disabled = true;
diff --git a/server.js b/server.js
index 4241918..f855cdb 100644
--- a/server.js
+++ b/server.js
@@ -33,6 +33,9 @@ const GAMES_DIR = process.env.DATA_DIR
   ? path.join(DATA_DIR, "gamejam-games")
   : path.join(PUBLIC_DIR, "gamejam-games");
 const MAX_UPLOAD = 5 * 1024 * 1024; /* 5 MB pro eingereichtem Spiel */
+
+/* Hart-Deadline für GameJam-Uploads: 27.05.2026, 22:00 Europe/Berlin (CEST = UTC+2). */
+const UPLOAD_DEADLINE = new Date("2026-05-27T22:00:00+02:00");
 const APP_REVISION = process.env.APP_REVISION || "local";
 
 function envFlag(name, defaultValue) {
@@ -345,6 +348,13 @@ function clamavPing() {
 
 /* ---------- GameJam: Spiel einreichen ---------- */
 function handleGamejamUpload(req, res) {
+  /* Hart-Deadline durchsetzen — danach werden keine Einreichungen mehr angenommen. */
+  if (Date.now() > UPLOAD_DEADLINE.getTime()) {
+    return sendJSON(res, 410, {
+      error: "Einreichungen sind seit dem 27.05.2026, 22:00 Uhr geschlossen."
+    });
+  }
+
   const ctype = req.headers["content-type"] || "";
   const bM = ctype.match(/boundary=(?:"([^"]+)"|([^;]+))/i);
   if (!/multipart\/form-data/i.test(ctype) || !bM) {