Bug [Next.js 16]: Vercel console warning about middleware missing

Hi! I recently upgraded to Next.js 16, and I’ve already run the codemod to migrate middleware.ts to proxy.ts as described here: https://nextjs.org/docs/messages/middleware-to-proxy

nextjs.org

Renaming Middleware to Proxy

Next.js by Vercel is the full-stack React framework for the web.

However, I’m getting the following warning when deploying:

WARNING: Unable to find source file for page middleware with extensions: tsx, ts, jsx, js, this can cause functions config from vercel.json to not be applied

I’m assuming this is a minor display thing and not actually an issue but wanted to confirm anyways. Thanks in advance!

I have the same problem and haven't found a solution yet.

I also facing same issues. What you meaning about this reply?

Vercel Staff

You can safely ignore this warning, it's a false positive for some code looking for a middleware.ts file and not recognizing proxy.ts as a valid alternative

There is an active PR to fix this

https://github.com/vercel/vercel/pull/14140

GitHub

Update middleware.ts warning for Next 16+ by swarnava · Pull Request #14140 · vercel/vercel

In Next.js 16+, middleware.ts is replaced by proxy.ts for Node.js runtime, though middleware.ts still works for Edge runtime cases. This change suppresses the 'Unable to find source file for pa...

Vercel Staff

Thank you so much for your patience while we worked on this. We wanted to let you know that we have just published a new version of the Vercel CLI on our build infrastructure. With this update, you should no longer see warnings about legacy middleware.ts when using Proxy files on Next.js v16+.

Please feel free to test it out, and let us know if you encounter any further issues. We're here to help!

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