diff --git a/lib/vidmoly-upload.js b/lib/vidmoly-upload.js
index d465ab2..25ebbbe 100644
--- a/lib/vidmoly-upload.js
+++ b/lib/vidmoly-upload.js
@@ -201,10 +201,16 @@ class VidmolyUploader {
       yield epilogueBuf;
     }
 
-    // Transit server lives on a different domain (*.vmwesa.online). Browsers
-    // don't send vidmoly.me cookies across origins, so we don't either.
-    // Origin + Referer match the browser's actual upload headers.
-    const { body, statusCode, headers } = await request(uploadUrl, {
+    // Transit server lives on a different domain (*.vmwesa.online) and runs
+    // the nginx-upload-progress module. It requires an X-Progress-ID query
+    // parameter on the POST URL — without it the upload hangs at the final
+    // byte because the module can't finalize the session. Browsers append it
+    // automatically before submitting the form.
+    const progressId = Date.now().toString() + Math.floor(Math.random() * 1e6).toString().padStart(6, '0');
+    const targetUrl = uploadUrl + (uploadUrl.includes('?') ? '&' : '?') + 'X-Progress-ID=' + progressId;
+
+    // Browsers don't send vidmoly.me cookies across origins, so we don't either.
+    const { body, statusCode, headers } = await request(targetUrl, {
       method: 'POST',
       body: generate(),
       signal,