diff --git a/src/backend/services/homepage/PuterHomepageService.ts b/src/backend/services/homepage/PuterHomepageService.ts
index 2a38744b7..9be7c0fee 100644
--- a/src/backend/services/homepage/PuterHomepageService.ts
+++ b/src/backend/services/homepage/PuterHomepageService.ts
@@ -185,6 +185,10 @@ export class PuterHomepageService extends PuterService {
             app_origin: this.#originFromRequest(req),
             gui_origin: this.#originFromRequest(req),
             hosting_domain: this.config.static_hosting_domain,
+            // The GUI loads the SDK itself in bundled mode, so it needs this
+            // to serve its own build rather than the public CDN.
+            puterjs_bundle:
+                this.config.gui_puterjs_bundle ?? 'https://js.puter.com/v2/',
             asset_dir: assetDir,
             captchaRequired,
             ...meta,
diff --git a/src/gui/src/index.js b/src/gui/src/index.js
index f39473dbf..f0f4a5cfd 100644
--- a/src/gui/src/index.js
+++ b/src/gui/src/index.js
@@ -75,7 +75,7 @@ window.gui = async (options) => {
     else if ( window.gui_env === 'prod' ) {
         // This stuff is now handled in the backend in PuterHomepageService
 
-        await window.loadScript('https://js.puter.com/v2/');
+        await window.loadScript(options.puterjs_bundle ?? 'https://js.puter.com/v2/');
         // Load the minified bundles
         // await window.loadCSS('/dist/bundle.min.css');
     }