Fix: Vercel Build Fails for Your Next.js App
Quick Answer
Run 'npm run build' locally first to catch the same errors Vercel sees. Most failures are TypeScript errors or missing environment variables.
Symptoms
- !Vercel shows 'Build Failed' in deployment dashboard
- !Build works locally but fails on Vercel
- !TypeScript errors only appear on Vercel
- !Missing environment variables in production
Step-by-Step Fix
Build locally first
Run 'npm run build' in your terminal. This catches most errors before deploying. Fix all errors shown.
Check environment variables
Go to Vercel Dashboard > Project > Settings > Environment Variables. Add all required variables (NEXT_PUBLIC_*, API keys, database URLs).
Fix TypeScript strict mode errors
Vercel builds in strict mode. Common fixes: add 'as' type assertions, fix 'any' types, handle null checks properly.
Check Node.js version
Vercel may use a different Node.js version. Set it in package.json: "engines": { "node": ">=18" } or in Vercel project settings.
Review build logs
Click on the failed deployment in Vercel dashboard. Read the build log from top to bottom — the first error is usually the root cause.
Frequently Asked Questions
Common reasons: missing env vars, different Node.js version, case-sensitive file imports (Linux vs macOS), or stricter TypeScript settings.
Add 'ignoreBuildErrors: true' to next.config.ts, but this is not recommended. Fix the actual errors instead.
Related
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