Claude Code
storage
Binary Files Corrupted During Upload or Processing
Files uploaded to or processed by your application come out corrupted. PDFs are unreadable, images show as broken, ZIP archives can't be extracted, and Excel files fail to open. The files appear to be the right size but their contents are garbled.
Binary file corruption typically happens when the application treats binary data as text (applying encoding transformations that destroy the data), when streams are not properly piped, or when files are read and written with mismatched encoding settings.
This issue is particularly insidious because it may only affect certain file types or file sizes, making it hard to reproduce consistently during testing.
Error Messages You Might See
Error: Invalid PDF structure
The file is corrupted and cannot be opened
Error: incorrect header check (zlib)
CairoError: invalid image surface
Corrupted ZIP: unexpected end of data
Common Causes
- UTF-8 encoding applied to binary data — Reading binary files with encoding: 'utf-8' instead of as a Buffer or bytes object
- Base64 double-encoding — File data is base64 encoded during upload and encoded again during storage, doubling the corruption
- Multipart parsing misconfigured — The file upload middleware converts binary data to strings instead of preserving raw buffers
- Stream not set to binary mode — HTTP response or file stream uses text mode instead of binary mode
- Chunked transfer truncation — Large files are cut off because the receiving end closes the connection before all chunks arrive
How to Fix It
- Always use binary mode for file operations — Use fs.readFile without encoding option (returns Buffer) or open files with 'rb'/'wb' in Python
- Verify multipart parsing configuration — Ensure multer, busboy, or your upload library preserves raw binary buffers
- Test with actual binary files — Upload a real PDF, image, and ZIP file and verify they open correctly after download. Compare checksums
- Use streams correctly — Pipe readable streams directly to writable streams without intermediate string conversion
- Check Content-Type headers — Ensure the response sets application/octet-stream or the correct MIME type, not text/plain
Real developers can help you.
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.
Vlad Temian
15+ years shipping production infrastructure for startups. Former CTO at qed.builders (acquired by The Sandbox).
Cursor ambassador and agentic tooling builder.
I've scaled systems, automated deployments, and built observability tools for AI coding workflows. I specialize in taking vibe-coded apps from broken prototype to production-ready: fixing Supabase auth/RLS, Stripe integrations, deployment pipelines, and cleaning up AI-generated spaghetti.
I build tools in this space (agentprobe, claudebin, micode) and understand both sides: how AI generates code and why it breaks.
https://blog.vtemian.com/
Yovel Cohen
I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well.
Costea Adrian
Embedded Engineer specilizing in perception systems. Latest project was a adas camera calibration system.
rayush33
JavaScript (React.js, React Native, Node.js) Developer with demonstrated industry experience of 4+ years, actively looking for opportunities to hone my skills as well as help small-scale business owners with solutions to technical problems
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.
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.
Krishna Sai Kuncha
Experienced Professional Full stack Developer with 8+ years of experience across react, python, js, ts, golang and react-native. Developed inhouse websearch tooling for AI before websearch was solved : )
Daniel Vázquez
Software Engineer with over 10 years of experience on Startups, Government, big tech industry & consulting.
Luca Liberati
I work on monoliths and microservices, backends and frontends, manage K8s clusters and love to design apps architecture
You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.
Get HelpFrequently Asked Questions
Why are my uploaded files corrupted?
The most common cause is reading binary files as text (UTF-8). Ensure your upload handler preserves raw binary buffers. In Node.js, don't pass an encoding option to fs.readFile for binary files.
How do I verify file integrity after upload?
Compare MD5 or SHA256 checksums of the original file and the stored file. If they differ, the data was modified during transit or storage. Use crypto.createHash in Node.js or hashlib in Python.