New Lovable app shows 404 on every page on Vercel

Since May 2026, all new Lovable applications utilize TanStack Start for building pages. These pages are generated on servers using Cloudflare Workers. However, this configuration results in a 404 NOT_FOUND error when these apps are deployed on Vercel, even if the deploy contains no pages at all. The vercel.json rewrite designed to rectify older Lovable applications does not resolve this issue and may exacerbate it.

The source of the problem lies in the fact that Vercel is unable to run the application built for Cloudflare Workers. To resolve this issue, developers must modify the project's package.json to identify if TanStack React Start is present. If found, the application should be rebuilt using Nitro, which is compatible with Vercel's detection and execution.

This involves installing Nitro and adding nitro() to the Vite plugins within vite.config.ts, alongside tanstackStart() and viteReact(). It is crucial not to create a Nitro preset and ensure Vercel is detected independently. The removal of any vercel.json rewrite directing to /index.html is also necessary, as server-rendered applications do not require this file.

Deploying the app directly to Cloudflare Workers using wrangler is also a viable solution, as it is compatible with the application's current setup. Alternatively, developers can use their AI tool to implement these changes. The modified build should be deployed on Vercel, and the app's functionality should remain unchanged when previewed in Lovable, Bolt, v0, Replit, or Cursor.

The only exception is when process.env.VERCEL is set, in which case Nitro should only be used. For further assistance, developers can refer to the full page detailing the necessary steps to resolve the 404 issue at launchpad.axonscape.com/fix/lovable-tanstack-start-404-on-vercel.