Fix Library ? Vercel
Vercel troubleshooting

Fix ?npm run build? Failed on Vercel

When Vercel fails at npm run build, reproduce the same command locally from a clean install. Most failures are missing dependencies, Node version mismatch, TypeScript errors, or incorrect output settings.

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Common symptoms

  • Vercel shows Command "npm run build" exited with 1.
  • The project runs locally with npm run dev but fails in production build.
  • The log mentions module not found, TypeScript, ESLint, or Node engine errors.

What to check first

Platform: Vercel
Error: npm run build failed

When Vercel fails at npm run build, reproduce the same command locally from a clean install. Most failures are missing dependencies, Node version mismatch, TypeScript errors, or incorrect output settings.

Step-by-step fix

  1. Run npm ci && npm run build locally to reproduce a production-like build.
  2. If the log says module not found, move the package from devDependencies to dependencies when it is needed at build/runtime.
  3. Set a Node version in package.json engines or Vercel project settings if the framework needs a specific version.
  4. Fix TypeScript/ESLint errors instead of disabling checks unless you are intentionally shipping a temporary preview.
{
  "scripts": { "build": "next build" },
  "engines": { "node": "20.x" }
}

# Clean local test
rm -rf node_modules package-lock.json
npm install
npm run build

Common mistake to avoid

Do not assume dev server success means deploy success. Production builds are stricter and catch missing imports, server/client boundary issues, and type errors.

Still stuck?

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