Local development is not the same test
A working next dev server does not establish that next build succeeds. On a safe authorised copy, compare the exact deployed revision, dependency lockfile, Node and package-manager versions, root directory and production build command. Use the application's declared scripts rather than assuming every Next.js version has identical commands or lint behaviour.
- Read the first useful error above the final exited-with-1 line.
- Record whether the build reaches compilation, type checking or prerendering.
- Do not disable checks merely to produce a deployable artifact.
No build log can mean no build started
Vercel documents failures before the build starts, including invalid configuration, contributor permissions and integration provisioning. If the Building logs are absent, inspect the provider's deployment error and provisioning stage. A suspended integration account is not an application code defect.
- Keep the redacted deployment ID and displayed error.
- Route account or billing issues to the account holder.
- Do not skip a provisioning dependency unless the build genuinely does not need it.
Compare configuration without leaking it
The local machine may have environment settings that are missing in a preview or production environment. Compare required variable names and presence, not secret values. Build-time requests may depend on private services; agree synthetic substitutes or safe access before reproducing them. Do not paste .env files into a support enquiry.
- Check the intended project root in a monorepo.
- Keep the same dependency installation and build sequence.
- Use debug-only build options on a safe copy, not a production release.
Acceptance boundary
A bounded repair proves the agreed production build on the intended preview route with original checks intact. It does not prove all runtime paths, a live production deployment or a Stripe subscription lifecycle. Include the baseline error, changed files, passing build evidence and separate deployment approval in the handover.
Sources and limits
- Next.js: CLI Checked 2026-10-10.
- next dev is development mode; next build creates a production build.
- next start requires a prior production build.
- Vercel: troubleshooting builds Checked 2026-10-10.
- Read the earlier useful error, not only the last build exit code.
- Some precondition and integration-provisioning failures occur before build logs exist.
- Build context includes root directory, Node version and package manager.