Hi @samuel-4300, I'm sorry you are facing this issue.

Is your Vercel project detecting the correct Framework preset in the Project Build settings? Make sure the defaults match your build script/output.

Can you also try running vercel build from your machine and see if the outcome is any difference?

Normally if this happens locally it’s because a module has registered a watcher or something that needs to be cleaned up.

Can you reproduce locally by running VERCEL=1 pnpm run build? As a debugging step, would you try adding another step in your build command, eg. pnpm run build && echo done so you can visually see if the nuxt build process has finished or not?

Thanks a lot for the quick replies – really appreciate it! Especially nice to see you in here @danielroe. After following your debugging suggestions I managed to figure out a temporary workaround, but I think it’s worth documenting what I did on my end since it might point to a deeper issue for investigation and I hope there's a better fix that can free me of my current workaround.

When testing locally earlier, I initially thought the build was completing fine on my end. But after trying again with your suggestion, I realized the same issue happens locally too – it’s just a bit more subtle. The terminal reports that the build has completed, but the process doesn’t actually exit. I can still press Cmd+C afterward to return to the prompt, which means the Node process is hanging even though the build appears done.

My ugly workaround was to add a Nitro hook to force the process to exit:

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nitro: {
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  hooks: {
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    close: () => {
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      if ((process.env.VERCEL || process.env.CI) && process.env.NODE_ENV === 'production') {
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        process.exit(0)
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      }
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    }
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  }
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}

That fixed the hanging issue, but it seemingly introduced another one: once I added the hook, the build started failing because my tsconfig.json extends from "./.nuxt/tsconfig.json", which apparently isn’t accessible when Vite parses it during the build – maybe as a side effect of the hook I added? I had to remove the extends and inline the config to get it working again.

So everything builds now, but I’m no longer extending from the .nuxt tsconfig. It seems like something in Nitro’s lifecycle is keeping the event loop alive when it should have exited cleanly. It might also affect other CI environments where the process needs to terminate automatically.

Does this sound like a known issue, or something that might need a deeper look on the Nuxt/Nitro side? For the record, this is all happening in my side project – which is a public repo. You can likely reproduce the issue by forking the monorepo, removing the Nitro hook I added, and trying to deploy the blog app to Vercel on your end - or just trying to build and observing that the process doesn't return back to the terminal prompt when its "done."

Repo: https://github.com/UmbraJS/mono

GitHub

GitHub - UmbraJS/mono: Modern theme management for the web A flexible, type-safe theme management library that creates semantic color systems based on the Umbra pattern - focusing on color relationships rather than specific element styling.

Modern theme management for the web A flexible, type-safe theme management library that creates semantic color systems based on the Umbra pattern - focusing on color relationships rather than spec...

Im having the same issue. I ran all these commands `vercel build, `VERCEL=1 bun run build , `bun run build && echo done` and got the same result. I can cancel the process and run vercel deploy and that works.