Cursor integration

Vercel and Netlify Build Errors on Cursor-Generated Projects

Your Cursor-generated project builds and runs perfectly locally with npm run dev, but deploying to Vercel or Netlify fails with build errors. The platform's build log shows module resolution failures, SSR compatibility errors, missing dependencies, or Next.js/Nuxt-specific issues that didn't appear during development.

Vercel and Netlify run production builds in a clean environment, which exposes issues hidden by your local development setup. Hot module replacement (HMR) and development-mode error recovery mask problems that surface in production builds. Additionally, these platforms have specific requirements for server-side rendering, API routes, and static generation that differ from local development servers.

Each failed deploy means another round of pushing a fix and waiting 1-3 minutes for the build to run, making the feedback loop painfully slow compared to local development.

Error Messages You Might See

Build error: Module not found: Can't resolve 'package-name' ReferenceError: window is not defined Error: Failed to collect page data for / Build exceeded maximum allowed duration (45 minutes) Error: Environment variable not found: NEXT_PUBLIC_API_URL Export encountered errors on following paths: /dynamic-page
Build error: Module not found: Can't resolve 'package-name'ReferenceError: window is not definedError: Failed to collect page data for /Build exceeded maximum allowed duration (45 minutes)Error: Environment variable not found: NEXT_PUBLIC_API_URLExport encountered errors on following paths: /dynamic-page

Common Causes

  • Dependencies in devDependencies instead of dependencies — Cursor installed packages as devDependencies that are needed at build time. Vercel/Netlify may not install devDependencies in production builds
  • Server-side code using browser APIs — Cursor generated code that references window, document, or localStorage in components that run during SSR, causing ReferenceError on the server
  • Missing build-time environment variables — Environment variables used during the build (like API URLs, public keys) aren't configured in the Vercel/Netlify dashboard
  • Node.js version mismatch — The platform uses a different Node.js version than your local machine. Cursor may have used syntax or APIs from a newer Node version
  • Dynamic imports not handled for static generation — Pages that use dynamic data are configured for static export but can't be pre-rendered without the data source
  • Monorepo or workspace configuration issues — The platform can't find the correct root directory or build command in a monorepo setup

How to Fix It

  1. Check the build logs carefully — The exact error message and the file/line it points to are your best debugging tools. Most build failures have a specific, fixable cause in the logs
  2. Guard browser API usage — Wrap browser-only code in checks: if (typeof window !== 'undefined') { /* browser code */ } or use Next.js dynamic imports with { ssr: false }
  3. Configure environment variables on the platform — Add all required env vars in the Vercel/Netlify dashboard. For build-time vars in Next.js, prefix with NEXT_PUBLIC_
  4. Pin the Node.js version — Add "engines": { "node": ">=18" } to package.json, or set the NODE_VERSION environment variable on the platform
  5. Run the production build locally first — Execute npm run build locally to catch the same errors before deploying. This replicates what the platform does
  6. Move build-time packages to dependencies — If a package is used during build or SSR, it must be in dependencies, not devDependencies

Real developers can help you.

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I regularly enjoy working on software products outside of work, and I'm a huge fan of game development using Unity. I personally enjoy Python & C# in my spare time, but I also specialise in multiple different platform-related technologies from my day job. legrab legrab I'll fill this later Franck Plazanet Franck Plazanet I am a Strategic Engineering Leader with over 8 years of experience building high-availability enterprise systems and scaling high-performing technical teams. My focus is on bridging the gap between complex technology and business growth. Core Expertise: 🚀 Leadership: Managing and coaching teams of 15+ engineers, fostering a culture of accountability and continuous improvement. 🏗️ Architecture: Enterprise Core Systems, Multi-system Integration (ERP/API/ETL), and Core Database Structure. ☁️ Cloud & Scale: AWS Expert; architected systems handling 10B+ monthly requests and managing 100k+ SKUs. 📈 Business Impact: Aligning tech strategy with P&L goals to drive $70k+ in monthly recurring revenue. I thrive on "out-of-the-box" thinking to solve complex technical bottlenecks and am always looking for ways to use automation to improve business productivity. ISHANTDEEP SINGH ISHANTDEEP SINGH Senior Software Engineer with 7+ years of experience in React, JavaScript, TypeScript, Next.js, and Node.js. I’ve also worked as a tech lead for startups, owning end-to-end technical execution including architecture, development, scaling, and delivery. I bring a strong mix of hands-on coding, product thinking, and technical leadership, and I’m comfortable building products from scratch as well as improving and scaling existing systems. Alvin Voo Alvin Voo I’ve watched the tech landscape evolve over the last decade—from the structured days of Java Server Pages to the current "wild west" of Agentic-driven development. While AI can "vibe" a frontend into existence, I specialize in the architecture that keeps it from collapsing. My expertise lies in the critical backend infrastructure: the parts that must be fast, secure, and scalable. I thrive on high-pressure environments, such as when I had only three weeks to architect and launch an Ethereum redemption system with minimal prior crypto knowledge, turning it into a major revenue stream. 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Frequently Asked Questions

Why does my app work with npm run dev but fail on Vercel?

npm run dev uses a development server with hot reloading that's more forgiving. The production build (npm run build) runs static analysis, tree shaking, and SSR that expose issues hidden in development. Always test with npm run build locally before deploying.

How do I fix 'window is not defined' on Vercel?

This happens when server-side rendering (SSR) tries to run browser-only code. Wrap browser API usage in if (typeof window !== 'undefined') checks, or use Next.js dynamic() with ssr: false for components that require the browser environment.

Related Cursor Issues

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