Can't find module "cloudflare:workers" when using `target: 'cloudflare-module'`

[astralarya]

Which project does this relate to?

Start

Describe the bug

Create a project with target: 'cloudflare-module' and add a CloudFlare durable object class.

I have created a minimal repo based on the start-basic template.

Your Example Website or App

https://github.com/astralarya/tanstack-start-cloudflare-durable-objects

Steps to Reproduce the Bug or Issue

Clone the repo linked above and run:

npm install
npm run dev

Then visit the locally hosted webpage (probably at port 3000).

Expected behavior

Wrangler should be able to simulate Durable Objects locally during development. Instead, visiting the local webpage gives the following error:

Error: Cannot find module 'cloudflare:workers' imported from '/path/to/repo/tanstack-start-cloudflare-durable-objects/src/utils/durable.ts'

Screenshots or Videos

No response

Platform

• Router / Start Version: 1.128.1
• OS: MacOS
• Browser: Chrome
• Browser Version: 138.0.7204.49
• Bundler: vite
• Bundler Version: v6.3.5

Additional context

The module "cloudflare:workers" is not a regular npm package, but something provided by the Cloudflare runtime in production and Wrangler during development.

[astralarya]

Does anyone have pointers on where to start? I would be happy to help write a fix for this issue

[irian-codes]

I suffer from this issue from time to time. Right now I'm facing it again and the fix was to change this:

import { ShipmentGroupService, type ShipmentGroup } from 'core'

to

import type { ShipmentGroup } from 'core'
import { ShipmentGroupService, } from 'core'

The error only shows up on frontend logs and says Uncaught TypeError: error loading dynamically imported module

[utopyin]

hi! Have you tried specifying the module as external?

In vite.config.ts:

import { tanstackStart } from "@tanstack/react-start/plugin/vite";
import viteReact from "@vitejs/plugin-react";
import { defineConfig } from "vite";
import tsConfigPaths from "vite-tsconfig-paths";

export default defineConfig({
  build: {
    target: "esnext",
    rollupOptions: {
      external: ["cloudflare:workers"],
    },
  },
  plugins: [
    tsConfigPaths({
      projects: ["./tsconfig.json"],
    }),
    tanstackStart({
      target: "cloudflare-module",
      customViteReactPlugin: true,
    }),
    viteReact(),
  ],
});

[schiller-manuel]

start now supports the cloudflare vite plugin
please have a look https://tanstack.com/start/latest/docs/framework/react/hosting#cloudflare-workers--official-partner

if there is still an issue, please open a new github issue