Adding proxy causes requests to _next/data which return empty data

[ari-party]

Link to the code that reproduces this issue

https://github.com/ari-party/repro-next-data-empty-object

To Reproduce

1. Clone this repo
2. npm install
3. npm run build
4. npm start
5. Go to http://localhost:3000
6. Open DevTools
7. Go to the network tab
8. Notice each additional _next/data request for each link to a page
9. Open any of the requests
10. View the response tab
11. Empty JSON response {}

Current vs. Expected behavior

Current: Requests made to _next/data/*/*.json
Expected: No requests made to _next/data/*/*.json
These empty data files bring no value and may cause a client error if the app is rebuilt, even if assetPrefix with hash is used.

Provide environment information

Operating System:
  Platform: linux
  Arch: x64
  Version: #35~22.04.1-Ubuntu SMP Mon May 26 18:08:30 UTC 2025
  Available memory (MB): 7944
  Available CPU cores: 2
Binaries:
  Node: 24.11.1
  npm: 11.6.2
  Yarn: 1.22.22
  pnpm: 10.23.0
Relevant Packages:
  next: 16.1.6 // Latest available version is detected (16.1.6).
  eslint-config-next: 13.5.6
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 5.3.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

Middleware, Pages Router

Which stage(s) are affected? (Select all that apply)

next start (local)

Additional context

This a recreation of an older issue #59295.
This issue is present for both the deprecated middleware and the newer proxy.

Additionally might be related: #59612

[yue4u]

barely a workaround but it seems it's possible to do something in next.config.js like below if the middleware is safe

  webpack: (config, { isServer }) => {

    // avoid middleware _next/data requests
    if (!isServer) {
      for (const plugin of config.plugins) {
        // replace next.js builtin DefinePlugin data
        if (
          plugin instanceof DefinePlugin &&
          plugin.definitions?.['process.env.__NEXT_MIDDLEWARE_MATCHERS']
        ) {
          plugin.definitions['process.env.__NEXT_MIDDLEWARE_MATCHERS'] = '[]'
          break
        }
      }
    }
  }

[christopherjohnson3028-stack]

Thank you for sharing this workaround. I will test the webpack configuration changes in next.config.js to see if defining process.env.__NEXT_MIDDLEWARE_MATCHERS as an empty array resolves the issue with the _next/data requests in my environment.

…

On Thu, Apr 9, 2026, 12:40 AM yue ***@***.***> wrote: *yue4u* left a comment (vercel/next.js#89768) <#89768 (comment)> barely a workaround but it seems it's possible to do something in next.config.js like below if the middleware is safe webpack: (config, { isServer }) => { // avoid middleware _next/data requests if (!isServer) { for (const plugin of config.plugins) { // replace next.js builtin DefinePlugin data if ( plugin instanceof DefinePlugin && plugin.definitions?.['process.env.__NEXT_MIDDLEWARE_MATCHERS'] ) { plugin.definitions['process.env.__NEXT_MIDDLEWARE_MATCHERS'] = '[]' break } } } } — Reply to this email directly, view it on GitHub <#89768 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B67D5GNQFBSK6MSDATL3ECL4U4ZURAVCNFSM6AAAAACUUDMEMOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DEMJRG4YDGNRTGQ> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>