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Vercel build errorVercel: “Command "npm run build" exited with 1”

The deployment fails and the last line of the log says Command "npm run build" exited with 1. That line is the wrapper, not the error: the build stopped earlier, and the reason is further up. Here’s how to find the real error, in Vercel’s words, and the pages for the usual ones, or hand it over at a fixed price.

Short answer

Open the failed deployment, expand Building in the build logs, and scroll up from the exit line to the first red error. That message is the problem: a type error, a missing module, a missing environment variable or a page that fails while prerendering. Run npm run build on your own machine to reproduce it, fix it, then push again.

Find the first error, then the usual causes

  1. 01

    The exit line isn’t the error

    “In many cases, the last mention is not indicative like in the example below where it says yarn run build exited with 1.” Vercel, Troubleshooting Build Errors

    Scroll up from it to the first error. Vercel’s own guide uses the same pattern, with yarn, as its example.

  2. 02

    Reproduce it locally

    “It is recommended to build your project on your local machine first (the build command varies per project) before deploying on Vercel.” Vercel, Troubleshooting Build Errors

    Run the same build command on your machine with a clean install. If it passes locally, the difference is the environment: variables, Node version or file name casing.

  3. 03

    Type and lint errors

    A production build checks types across the whole project, so an error in a file the dev server never loaded can still stop it. Fix the errors the log lists rather than turning the checks off.

  4. 04

    A missing environment variable

    Code that reads a variable while building, such as an API URL or a database string, fails when it isn’t set for that Vercel environment. Add it for Production and Preview and redeploy.

Checked against the vendor’s docs on : Vercel docs: Troubleshooting build errors.

Rather hand it over?

Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed.

Related: Vercel Module not found: Can’t resolve · Vercel environment variables undefined · Next.js DynamicServerError at build · Next.js window is not defined

Questions

More on this error

What if there is no build log at all?

Vercel says builds can fail without logs when a precondition stops the build from starting, and then shows the error message in an overlay instead. Read that message.

What do you need to fix it?

The repository and the failed deployment’s build log, or a screenshot of the first error above the exit line.

Can you fix it for me?

If one bug is the whole problem, the App Fix Ticket covers it: a written diagnosis first, then the fix. If the app has more going on, the Launch Check is a written check of the whole app. Each issue found is rated critical, high, medium or low, with where it is and how it was confirmed. No issues worth fixing, no charge. If the Launch Check finds nothing rated medium or higher, Simon refunds the full $450. You keep the report either way.

A different error?

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Send the error and what you were doing. You get a written scope, a fixed price and a timeline; we reply by email, usually within one business day.

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