Expose whether a route isServerOnly so locale rewrites can avoid server-only routes

[jasongitmail]

Feature Request

I’m using rewrite.input for locale-prefixed routes.

Desired Behavior

• /es/contact -> internally route to /contact
• /es/robots.txt -> 404, not /robots.txt
• /es/sitemap.xml -> 404, not /sitemap.xml
• /es/api/foo -> 404, not /api/foo

Current API Limitation

Today rewrite.input({ url }) runs before route matching and only receives the public URL.

That means I can turn /es/robots.txt into /robots.txt, but the rewrite function has no supported way to know that the candidate internal URL /robots.txt points to a server-only route. So the same locale stripping logic that works for pages also makes localized variants of server-only routes accessible.

By “server-only route,” I mean a route handled by server.handlers that does not render a UI/page route for navigation.

Current Workaround

Traverse routeTree and inspect runtime option shape like route.options.server?.handlers, but that feels like relying on internals.

Feature Request / Suggestion

Would TanStack consider exposing a supported way for rewrite.input to inspect the route for a candidate internal URL, including whether that route is server-only?

A possible shape:

rewrite: {
  input: ({ url, getRoute }) => {
    const locale = getLocaleFromPathname(url.pathname); // app specific

    if (!locale) {
      return url;
    }

    const strippedUrl = new URL(url);
    strippedUrl.pathname = stripLocalePrefix(url.pathname); // app specific

    const strippedRoute = getRoute(strippedUrl);

    return strippedRoute?.isServerOnly ? url : strippedUrl;
  },
}

The exact API shape does not matter. The key capability is: rewrite logic can inspect the route for the candidate internal URL before deciding whether to return the original URL or the candidate URL.

[jasongitmail]

that's a clean workaround too, but does require manually maintaining a list of all server paths