Next.js 16 Build Hangs Indefinitely in SWC Compile Phase on Vercel

What this error means

next build hangs indefinitely in SWC compile phase — reproduces on every Next 16 release (16.0.0, 16.2.6, 16.3.0-canary.19) is a Vercel failure pattern reported for developers trying to fix next.js 16 production build hanging forever during swc compilation on vercel deployment. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub issue #93880 on vercel/next.js: next build hangs indefinitely in SWC compile phase on Next 16. Reproduces on macOS arm64 AND Linux x86_64 (Vercel cloud). Last known good: next@15.5.18. Affects both webpack and Turbopack bundlers. Blocks deployment for Vercel paying customers upgrading to Next 16.

Common causes

• GitHub issue #93880 on vercel/next.js: next build hangs indefinitely in SWC compile phase on Next 16. Reproduces on macOS arm64 AND Linux x86_64 (Vercel cloud). Last known good: next@15.5.18. Affects both webpack and Turbopack bundlers. Blocks deployment for Vercel paying customers upgrading to Next 16.

Quick fixes

1. Confirm the exact error signature matches next build hangs indefinitely in SWC compile phase — reproduces on every Next 16 release (16.0.0, 16.2.6, 16.3.0-canary.19).
2. Check the Vercel account, local tool state, and provider configuration involved in the failing workflow.
3. Check the build output, project root, and deployment platform configuration before redeploying.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/vercel/next.js/issues/93880

Evidence note: GitHub issue #93880 on vercel/next.js: next build hangs indefinitely in SWC compile phase on Next 16. Reproduces on macOS arm64 AND Linux x86_64 (Vercel cloud). Last known good: next@15.5.18. Affects both webpack and Turbopack bundlers. Blocks deployment for Vercel paying customers upgrading to Next 16.

Related errors

• Deployment

FAQ

What should I check first?

Start with the exact next build hangs indefinitely in SWC compile phase — reproduces on every Next 16 release (16.0.0, 16.2.6, 16.3.0-canary.19) text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Vercel workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without next build hangs indefinitely in SWC compile phase — reproduces on every Next 16 release (16.0.0, 16.2.6, 16.3.0-canary.19).