Cursor Project Fails on Vercel Build
Quick Answer
Cursor often gets the app working in development mode first. Production builds fail when imports are wrong, environment variables are missing, or TypeScript errors are ignored locally. Start with "Run the production build locally" before making broader code changes.
Quick Fix Summary
| Most likely cause | Cursor often gets the app working in development mode first. Production builds fail when imports are wrong, environment variables are missing, or TypeScript errors are ignored locally. |
| Fastest fix | Run the production build locally |
| Use this page if | The app works locally but Vercel build fails |
You're in the right place if...
- !The app works locally but Vercel build fails
- !Deployment log shows TypeScript or module errors
- !Production build breaks after AI-generated changes
Why this happens
Cursor often gets the app working in development mode first. Production builds fail when imports are wrong, environment variables are missing, or TypeScript errors are ignored locally.
Fix
Run the production build locally
Before redeploying, run the exact production build command locally so you see the real failure instead of guessing.
npm run build
Fix the first red error only
Ignore the flood of follow-on errors. Read the first failing line in the build output and fix that root cause before touching anything else.
Check env vars and server/client boundaries
If the build references undefined env vars or browser APIs in server code, move them to the right runtime context and redeploy.
Prevent this next time
Make `npm run build` part of your Cursor workflow after every meaningful AI change. If it builds locally, deploy risk drops dramatically.
Frequently Asked Questions
Development mode is more forgiving. Production builds enforce stricter TypeScript, module, and server/client boundaries.
Reproduce it locally with `npm run build`, then fix the first real error instead of chasing the whole log.
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