Cursor
storage
File System Operations Failing in Production After Cursor Build
Your Cursor-generated application reads and writes files to the local file system, which works perfectly during local development but fails in production. The app crashes with ENOENT, EACCES, or EROFS errors when trying to create temp files, write uploads, or read generated content.
This is a common trap with AI-generated code. Cursor writes straightforward file system code using fs.writeFile, fs.readFile, or similar APIs because it's the simplest approach. But modern production environments — serverless functions (Vercel, AWS Lambda, Netlify), containerized deployments (Docker, Kubernetes), and PaaS platforms (Heroku, Railway) — either have read-only file systems, ephemeral storage that gets wiped between invocations, or no local disk at all.
The issue often surfaces only after deployment, when the first user triggers a file operation and gets a server error.
Error Messages You Might See
EROFS: read-only file system, open '/var/task/uploads/file.png'
ENOENT: no such file or directory, open './data/output.json'
EACCES: permission denied, mkdir '/app/temp'
Error: ENOSPC: no space left on device
EPERM: operation not permitted, write
Common Causes
- Read-only file system in production — Serverless platforms and containerized environments mount the application directory as read-only
- Ephemeral storage between invocations — Files written in one Lambda/serverless invocation are gone in the next
- Hardcoded local paths — Cursor generated paths like /tmp/uploads or ./data that don't exist or aren't writable in production
- /tmp directory size limits — Even when /tmp is writable (as in Lambda), it has strict size limits (512MB default) that are easily exceeded
- Missing directory creation — Code writes to nested directories without first creating them with mkdirSync/mkdir -p
- File path separators — Windows-style backslash paths generated during development fail on Linux production servers
How to Fix It
- Replace local file ops with cloud storage — Use S3, Supabase Storage, Cloudflare R2, or Google Cloud Storage instead of the local file system for any persistent file operations
- Use /tmp only for transient operations — If you must use local files (e.g., for image processing), write to /tmp and clean up immediately after. Never rely on files persisting
- Stream instead of buffering — Instead of writing a file to disk and then uploading it, stream data directly from the source to the destination
- Check for platform-specific storage APIs — Vercel has vercel/blob, Netlify has Netlify Blobs. Use platform-native storage when available
- Add fallback error handling — Wrap file operations in try/catch and provide meaningful error messages when the file system is unavailable
- Use environment detection — Check
process.env.NODE_ENVor platform-specific env vars to choose between local and cloud storage
Real developers can help you.
Richard McSorley
Full-Stack Software Engineer with 8+ years building high-performance applications for enterprise clients. Shipped production systems at Walmart (4,000+ stores), Cigna (20M+ users), and Arkansas Blue Cross. 5 patents in retail/supply chain tech. Currently focused on AI integrations, automation tools, and TypeScript-first architectures.
Jacek Rozanski
Senior PHP/Symfony developer and DevOps engineer with 20+ years of professional experience, running opcode.pl (web development agency, est. 2004).
Day job: I'm the sole backend developer at merketing company where I own and maintain 11 PHP/Symfony microservices on AWS (ECS Fargate, RDS, S3, CloudFront), handle the full CI/CD pipeline (Bitbucket Pipelines, Docker), and manage monitoring with Sentry and CloudWatch. These services handle high request volumes in production every month.
What I bring to AI-built apps:
- I audit and fix security issues (OWASP methodology), performance bottlenecks, and architectural problems in codebases generated by Cursor, Claude Code, Lovable, Bolt, and v0
- I refactor AI-generated prototypes into production-grade applications with proper error handling, testing, and clean architecture (SOLID, DDD, hexagonal architecture)
- I set up the infrastructure AI tools don't touch: AWS hosting, CI/CD pipelines, automated deployments, database optimization, monitoring, and alerting
- I integrate external services: payment providers, email systems, partner APIs, SSO/auth
Tech stack: PHP 8.x, Symfony, React, Next.js, PostgreSQL, MySQL, Docker, AWS (ECS, RDS, S3, SQS/SNS, CloudFront), Terraform, Supabase. I also use AI tools daily (Claude Code, Cursor) in my own workflow, so I understand both the strengths and the gaps in AI-generated code.
Based in Poland (CET timezone). Available for async work and calls during EU/US business hours.
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.
Matt Butler
Software Engineer @ AWS
Mehdi Ben Haddou
- Founder of Chessigma (1M+ users) & many small projects
- ex Founding Engineer @Uplane (YC F25)
- ex Software Engineer @Amazon and @Booking.com
Dor Yaloz
SW engineer with 6+ years of experience,
I worked with React/Node/Python
did projects with React+Capacitor.js for ios
Supabase expert
Antriksh Narang
5 years+ Experienced Dev (Specially in Web Development), can help in python, javascript, react, next.js and full stack web dev technologies.
Anthony Akpan
Developer with 8 years of experience building softwares fro startups
Caio Rodrigues
I'm a full-stack developer focused on building practical and scalable web applications. My main experience is with **React, TypeScript, and modern frontend architectures**, where I prioritize clean code, component reusability, and maintainable project structures.
I have strong experience working with **dynamic forms, state management (Redux / React Hook Form), and complex data-driven interfaces**. I enjoy solving real-world problems by turning ideas into reliable software that companies can actually use in their daily operations.
Beyond coding, I care about **software quality and architecture**, following best practices for componentization, code organization, and performance optimization.
I'm also comfortable working across the stack when needed, integrating APIs, handling business logic, and helping transform prototypes into production-ready systems.
My goal is always to deliver solutions that are **simple, efficient, and genuinely useful for the people using them.**
AUXLE
I am a Full Stack Developer experienced in building Websites, Web apps and Cross Platform Mobile Apps for Startups and Companies.
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
Can I write files at all in serverless environments?
Most serverless platforms allow writing to the /tmp directory, but the space is limited (512MB on AWS Lambda) and files are deleted between invocations. For persistent storage, use a cloud storage service like S3 or Supabase Storage.
How do I handle file uploads without local storage?
Stream uploads directly to cloud storage using multipart upload APIs. Libraries like multer-s3 for Express or @aws-sdk/lib-storage for direct S3 uploads handle this without writing to disk.