Tanstack Start prerender broken with Nitro v3 on Vercel

[josippapez]

Environment

Both nitro v3 and v2.
Node v24.12.0

Reproduction

Here's the reproducible:
https://github.com/josippapez/tanstack-vercel-reproducible

Describe the bug

I get the following error:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/my-app/.output/server/server.js' imported from /my-app/node_modules/.pnpm/@tanstack+start-plugin-core@1.141.5_@tanstack+react-router@1.141.4_react-dom@19.2.3_rea_8f07dd2dc4f2e030cbea330a30ef30f3/node_modules/@tanstack/start-plugin-core/dist/esm/preview-server-plugin/plugin.js
    at finalizeResolution (node:internal/modules/esm/resolve:274:11)
    at moduleResolve (node:internal/modules/esm/resolve:864:10)
    at defaultResolve (node:internal/modules/esm/resolve:990:11)
    at nextResolve (node:internal/modules/esm/hooks:785:28)
    at o (file:///my-app/node_modules/.pnpm/@tailwindcss+node@4.1.18/node_modules/@tailwindcss/node/dist/esm-cache.loader.mjs:1:69)
    at nextResolve (node:internal/modules/esm/hooks:785:28)
    at AsyncLoaderHooksOnLoaderHookWorker.resolve (node:internal/modules/esm/hooks:271:30)
    at MessagePort.handleMessage (node:internal/modules/esm/worker:251:24)
    at [nodejs.internal.kHybridDispatch] (node:internal/event_target:845:20)
    at MessagePort.<anonymous> (node:internal/per_context/messageport:23:28)

For this vite.config.ts

import { defineConfig } from 'vite';
import { tanstackStart } from '@tanstack/react-start/plugin/vite';
import viteReact from '@vitejs/plugin-react';
import viteTsConfigPaths from 'vite-tsconfig-paths';
import tailwindcss from '@tailwindcss/vite';
import { nitro } from 'nitro/vite';

const config = defineConfig({
  build: {
    sourcemap: true,
    outDir: '.output',
    emptyOutDir: true,
    target: 'es2022',
    minify: true,
    rollupOptions: {
      treeshake: true,
      output: {
        manualChunks: (id: string) => {
          if (
            id.includes('phone/dist') ||
            id.includes('react-phone-number-input')
          ) {
            return 'phone';
          }

          if (id.includes('lodash')) {
            return 'lodash';
          }

          if (id.includes('country-flag-icons')) {
            return 'country-flag-icons';
          }

          if (id.includes('medusa')) {
            return 'medusa';
          }
        },
      },
    },
  },
  plugins: [
    // this is the plugin that enables path aliases
    viteTsConfigPaths({
      projects: ['./tsconfig.json'],
    }),
    tailwindcss(),
    tanstackStart(),
    nitro({
      preset: 'vercel',
      output: {
        dir: '.output',
        serverDir: '.output/server',
        publicDir: '.output/static',
      },
      routeRules: {
        // Cache fonts for 1 year (immutable)
        '/fonts/**': {
          headers: {
            'Cache-Control': 'public, max-age=31536000, immutable',
          },
        },
        // Cache images for 1 month
        '/**/*.{jpg,jpeg,png,gif,webp,svg,ico}': {
          headers: {
            'Cache-Control': 'public, max-age=2592000',
          },
        },
        // cache css
        '/**/*.{css}': {
          headers: {
            'Cache-Control': 'public, max-age=604800',
          },
        },
      },
    }),
    viteReact(),
  ],
  resolve: {
    alias: {
      '/fonts': '/public/fonts',
    },
  },
  ssr: {
    noExternal: ['@radix-ui/*', '@medusajs/*', 'nuqs'],
  },
});

export default config;

I did try invoking server.js/index.mjs directly with pnpm serve and node .output/server/index.mjs.

and then i try to pnpm dev (works), pnpm build passes and then pnpm preview and node index.mjs directly, and the node one doesn't start while the preview returns the same error as above

Additional context

No response

Logs

[pi0]

Have you tried removing output config? setting it manually can break deployment.

(PS: There is no supported nitro v2 vite plugin (for tanstack start) only nitro v3.)

[agustinusnathaniel]

Also reproduced on my side
Deploying tanstack start app to vercel with prerendering on latest tanstack start and latest nitro-nightly

Using nitro v3

Here's my package.json:

{
  ...,
  "dependencies": {
    ...,
    "@tanstack/react-router": "1.144.0",
    "@tanstack/react-start": "1.145.3",
    ...
  },
  "devDependencies": {
    ...,
    "nitro": "npm:nitro-nightly@3.0.1-20251230-165713-6e801e22",
    ...
  }
}

Here's my vite.config.ts:

import { ValidateEnv } from '@julr/vite-plugin-validate-env';
import tailwindcss from '@tailwindcss/vite';
import { tanstackStart } from '@tanstack/react-start/plugin/vite';
import viteReact from '@vitejs/plugin-react';
import { nitro } from 'nitro/vite';
import { defineConfig } from 'vite';
import tsConfigPaths from 'vite-tsconfig-paths';

export default defineConfig(({ mode }) => {
  return {
    plugins: [
      ValidateEnv(),
      nitro(),
      tanstackStart({
        prerender: {
          enabled: true,
        },
      }),
      viteReact(),
      tailwindcss(),
      tsConfigPaths(),
    ],
    server: {
      open: true,
    },
  };
});

Then during build there's this error:

Error [ERR_MODULE_NOT_FOUND]: Cannot find module '/vercel/path0/dist/server/server.js' imported from /vercel/path0/node_modules/.pnpm/@tanstack+start-plugin-core@1.145.3_@tanstack+react-router@1.144.0_react-dom@19.2.3_rea_c707235fe1fd544c0836fd0b2566205c/node_modules/@tanstack/start-plugin-core/dist/esm/preview-server-plugin/plugin.js
    at finalizeResolution (node:internal/modules/esm/resolve:274:11)
    at moduleResolve (node:internal/modules/esm/resolve:864:10)
    at defaultResolve (node:internal/modules/esm/resolve:990:11)
    at nextResolve (node:internal/modules/esm/hooks:785:28)
    at o (file:///vercel/path0/node_modules/.pnpm/@tailwindcss+node@4.1.18/node_modules/@tailwindcss/node/dist/esm-cache.loader.mjs:1:69)
    at nextResolve (node:internal/modules/esm/hooks:785:28)
    at AsyncLoaderHooksOnLoaderHookWorker.resolve (node:internal/modules/esm/hooks:269:30)
    at MessagePort.handleMessage (node:internal/modules/esm/worker:251:24)
    at [nodejs.internal.kHybridDispatch] (node:internal/event_target:845:20)
    at MessagePort.<anonymous> (node:internal/per_context/messageport:23:28)

[josippapez]

Have you tried removing output config? setting it manually can break deployment.

(PS: There is no supported nitro v2 vite plugin (for tanstack start) only nitro v3.)

Sorry, the missing notifications feature on github is killing me...
Yes, i did, i did try with:

nitro({
      preset: 'vercel',
      routeRules: {
        // Cache fonts for 1 year (immutable)
        '/fonts/**': {
          headers: {
            'Cache-Control': 'public, max-age=31536000, immutable',
          },
        },
        // Cache images for 1 month
        '/**/*.{jpg,jpeg,png,gif,webp,svg,ico}': {
          headers: {
            'Cache-Control': 'public, max-age=2592000',
          },
        },
        // cache css
        '/**/*.{css}': {
          headers: {
            'Cache-Control': 'public, max-age=604800',
          },
        },
      },
    }),

and it didn't fix anything, also, even without routeRules it's still the same (only gaving preset in the nitro)

[pi0]

Please provide a minimal reproduction. (also try latest tss and nitro nightly, tss prerender started to break at somepoint)

[EthanShoeDev]

Was also hitting this bug. I got opus 4.5 to use bun patch and it eventually worked with this.

nitro@3.0.1-alpha.1.patch

FYI - Not expecting this to be upstreamed. Just wanted to add it as reference.

[pi0]

Thanks for ref @EthanShoeDev. #3921 should fix preview command (therefore tss prerendering support) for vercel.

[agustinusnathaniel]

Still error during build on vercel with the latest nightly

 > - Date: 1/6/2026, 1:57:02 PM
 > - Nitro Version: 3.0.1-20260106-130706-e20c92d9
 > - Nitro Preset: vercel
[info] Spawning preview server...
[info] npx srvx --static ../../static ./functions/__server.func/index.mjs
npm warn Unknown env config "npm-globalconfig". This will stop working in the next major version of npm.
npm warn Unknown env config "verify-deps-before-run". This will stop working in the next major version of npm.
npm warn Unknown env config "_jsr-registry". This will stop working in the next major version of npm.
npm warn Unknown env config "enable-pre-post-scripts". This will stop working in the next major version of npm.
npm warn Unknown project config "enable-pre-post-scripts". This will stop working in the next major version of npm.
sh: line 1: srvx: command not found
[error] [nitro] Preview server exited with code 127
error during build:
Error: Failed to start the Vite preview server for prerendering
    at startPreviewServer (file:///vercel/path0/node_modules/.pnpm/@tanstack+start-plugin-core@1.145.8_@tanstack+react-router@1.145.7_react-dom@19.2.3_rea_429cef09745127f0fb47a14abe9bb1ae/node_modules/@tanstack/start-plugin-core/dist/esm/prerender.js:195:11)
    at async prerender (file:///vercel/path0/node_modules/.pnpm/@tanstack+start-plugin-core@1.145.8_@tanstack+react-router@1.145.7_react-dom@19.2.3_rea_429cef09745127f0fb47a14abe9bb1ae/node_modules/@tanstack/start-plugin-core/dist/esm/prerender.js:42:25)
    at async postServerBuild (file:///vercel/path0/node_modules/.pnpm/@tanstack+start-plugin-core@1.145.8_@tanstack+react-router@1.145.7_react-dom@19.2.3_rea_429cef09745127f0fb47a14abe9bb1ae/node_modules/@tanstack/start-plugin-core/dist/esm/post-server-build.js:38:5)
    at async BasicMinimalPluginContext.handler (file:///vercel/path0/node_modules/.pnpm/@tanstack+start-plugin-core@1.145.8_@tanstack+react-router@1.145.7_react-dom@19.2.3_rea_429cef09745127f0fb47a14abe9bb1ae/node_modules/@tanstack/start-plugin-core/dist/esm/plugin.js:285:11)
    at async Object.buildApp (file:///vercel/path0/node_modules/.pnpm/rolldown-vite@7.3.0_@types+node@25.0.3_esbuild@0.27.2_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/rolldown-vite/dist/node/chunks/node.js:33201:5)
    at async CAC.<anonymous> (file:///vercel/path0/node_modules/.pnpm/rolldown-vite@7.3.0_@types+node@25.0.3_esbuild@0.27.2_jiti@2.6.1_terser@5.44.1_tsx@4.21.0_yaml@2.8.2/node_modules/rolldown-vite/dist/node/cli.js:629:3)
 ELIFECYCLE  Command failed with exit code 1.
Error: Command "pnpm build" exited with 1

Unless I explicitly install srvx to package.json dependencies or devDependencies and then its successful or able to run.

Is this expected?