`cloudflare-module` ssr with trpc query + tanstack start not working

[rubenbase]

Environment

app.config.ts

import { defineConfig } from '@tanstack/start/config';
import tsConfigPaths from 'vite-tsconfig-paths';
import { cloudflare } from 'unenv';
import nitroCloudflareBindings from 'nitro-cloudflare-dev';

export default defineConfig({
  server: {
    preset: 'cloudflare-module',
    unenv: cloudflare,
    modules: [nitroCloudflareBindings],
  },
  vite: {
    plugins: [
      tsConfigPaths({
        projects: ['./tsconfig.json'],
      }),
    ],
  },
});

Reproduction

Download the trpc starter: https://github.com/trpc/trpc/tree/main/examples/tanstack-start

Change app.config.ts with the cloudflare-module settings:

import { cloudflare } from 'unenv';
import nitroCloudflareBindings from 'nitro-cloudflare-dev';
// ...
 server: {
    preset: 'cloudflare-module',
    unenv: cloudflare,
    modules: [nitroCloudflareBindings],
  },

Describe the bug

go to posts -> select a post -> refresh -> it crashes because of the loader in the $postid route.

Screen.Recording.2025-05-08.at.8.38.09.PM.mov

Additional context

This works when deployed to other platforms like Vercel.

Logs

TRPCClientError: Stream closed

[pi0]

Would you be able to create a minimal nitro reproduction with trpc only without tanstack-start? (if not, I would suggest to please consider opening an issue in tanstack-start repo)

[rubenbase]

Hey @pi0, it works with Vercel and Netlify, so thought It might be related to Nitro's cloudflare-module preset or potentially just a Cloudflare issue

[pi0]

It can be or not. Since there is a wrapper around nitro that can change behavior, we need minimal reproduction as first step to make sure it is actually an issue with nitro.

[rubenbase]

Debugged more, it's some configuration on CF or their firewall and not nitro.