Next.js dev server runs but localhost:5173 does not open on Windows + WSL

[primeautomation-dev]

Hi, I'm having an issue with Next.js dev server not opening in the browser.

Environment:

• Windows 11
• WSL2 (Ubuntu 22.04)
• Node.js v20 via nvm
• Next.js v14
• Project is located under /mnt/c

What happens:

• npm install works without errors
• npm run dev starts successfully
• Terminal shows:
  Local: http://localhost:5173
  Network: http://0.0.0.0:5173
• But when I open http://localhost:5173 in Windows browser, the page does not load (connection refused / not responding)

Extra notes:

• next.config.js currently has output: "export"
• I also see this warning:
  "Unrecognized key(s) in object: 'appDir' at 'experimental'"

Things I already tried:

• Reinstalling node modules
• Running dev with -H 0.0.0.0
• Running both from Windows and WSL
• Firewall disabled for testing

Question:
Is this related to output: "export" or WSL networking?
What is the correct way to run Next.js dev server in this setup?

Thanks in advance.

[AshkanPoyber]

Hi @primeautomation-dev.

This is a combination of WSL networking + project location + config.

Main issue

output: "export" is meant for static export builds, not for running the dev server.
When using next dev, it can cause unexpected behavior, especially under WSL.

What to fix

1. Remove output: "export" for development

In next.config.js, remove:

output: "export"


Use it only when you are doing:

next build
next export

2. Ignore the `appDir` warning
This warning:
`Unrecognized key(s) in object: 'appDir' at 'experimental'`
means you are on Next.js 14.

`appDir` is no longer needed under `experimental `and should be removed:

experimental: {
// remove appDir
}

3. Move the project out of `/mnt/c`
Running Next.js dev server from `/mnt/c` under WSL often causes filesystem and networking issues.

✅ Best practice:
`/home/your-user/projects/my-next-app`

Then reinstall:

rm -rf node_modules package-lock.json
npm install
npm run dev

4. Use default dev port
Port `5173` is usually associated with Vite.
For Next.js, let it run on the default port:
`http://localhost:3000`
or explicitly:
`npm run dev -- -p 3000`




**### Summary**

`output: "export"` should not be used with `next dev`

Remove deprecated `appDir` config

Avoid running Next.js dev server from `/mnt/c` in WSL

Run the project inside WSL filesystem

After these changes, the dev server should open correctly in the Windows browser

Hope this helps 👍