diff --git a/sandpack-client/src/clients/node/index.ts b/sandpack-client/src/clients/node/index.ts
index 0766ea367..644271438 100644
--- a/sandpack-client/src/clients/node/index.ts
+++ b/sandpack-client/src/clients/node/index.ts
@@ -182,7 +182,7 @@ export class SandpackNode extends SandpackClient {
 
     const { url } = await this.emulator.preview.getByShellId(id);
 
-    this.iframePreviewUrl = url + this.options.startRoute;
+    this.iframePreviewUrl = url + this.options.startRoute ?? "";
   }
 
   /**