Windsurf
storage
Blob Storage Corrupting Uploaded Files in Windsurf App
Files uploaded to blob storage through your Windsurf-generated app become corrupted when downloaded. PDFs are unreadable, images show garbled data, ZIP files fail to extract, and documents open as random characters. The upload appears to succeed, but the stored file is damaged.
This is a particularly insidious bug because uploads appear successful — no errors are thrown, the file shows up in storage, and the file size may even look correct. But when a user downloads and opens the file, it's broken.
The corruption typically affects binary files (images, PDFs, ZIPs) while text files may work fine, which is a strong clue that the issue is related to encoding or stream handling.
Error Messages You Might See
Error: Invalid or corrupted PDF
Failed to decode image
Error: End-of-central-directory signature not found (ZIP)
The file is damaged and could not be opened
UTF-8 decode error on binary data
Common Causes
- UTF-8 encoding applied to binary data — Cascade read the file as a UTF-8 string instead of a Buffer, destroying binary data during encoding conversion
- Base64 double-encoding — The file is base64-encoded before upload, but the storage client also encodes it, resulting in double-encoded data
- Wrong content-type on upload — The file is uploaded with content-type: text/plain or application/json instead of its actual MIME type
- Stream not piped correctly — The readable stream is consumed (read to string) before being passed to the storage upload, instead of being piped directly
- Multipart boundary parsing error — The multipart form parser mishandles the file boundaries, truncating or appending extra bytes
How to Fix It
- Always use Buffer for binary files — Never call toString() on file data. Use Buffer objects or ArrayBuffer throughout the upload pipeline
- Set the correct content-type — Detect the MIME type using the file-type library or the upload's mimetype field, and pass it to the storage upload call
- Avoid double-encoding — Check if your storage client already handles encoding. Don't base64-encode if the client expects a Buffer or stream
- Pipe streams directly — Instead of reading the entire file into memory, pipe the upload stream directly to the storage write stream
- Verify with checksums — Generate an MD5 hash before upload and after download to confirm the file is identical. If hashes differ, the corruption is in the upload path
- Test with binary files specifically — Upload a small PNG or PDF and download it immediately. Open it to verify integrity before shipping to production
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.
Pratik
SWE with 15+ years of experience building and maintaining web apps and extensive BE infrastructure
Tejas Chokhawala
Full-stack engineer with 5 years experience building production web apps using React, Next.js and TypeScript.
Focused on performance, clean architecture and shipping fast.
Experienced with Supabase/Postgres backends, Stripe billing, and building AI-assisted developer tools.
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.
What I bring to your project:
Forensic Debugging: I don't just "patch" bugs; I use tools like Datadog and Explain Analyzers to map out bottlenecks and resolve root causes—like significantly reducing memory usage by optimizing complex DB joins.
Full-Stack Context: Deep experience in Node.js and React, ensuring backends play perfectly with mobile and web teams.
Sanity in the Age of AI: I bridge the gap between "best practices" and modern speed, ensuring your project isn't just built fast, but built to last.
Daniel Vázquez
Software Engineer with over 10 years of experience on Startups, Government, big tech industry & consulting.
zipking
I am a technologist and product builder dedicated to creating high-impact solutions at the intersection of AI and specialized markets. Currently, I am focused on PropScan (EstateGuard), an AI-driven SaaS platform tailored for the Japanese real estate industry, and exploring the potential of Archify.
As an INFJ-T, I approach development with a "systems-thinking" mindset—balancing technical precision with a deep understanding of user needs. I particularly enjoy the challenge of architecting Vertical AI SaaS and optimizing Small Language Models (SLMs) to solve specific, real-world business problems. Whether I'm in a CTO-level leadership role or hands-on with the code, I thrive on building tools that turn complex data into actionable value.
Matthew Jordan
I've been working at a large software company named Kainos for 2 years, and mainly specialise in Platform Engineering. 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.
Matthew Butler
Systems Development Engineer @ Amazon Web Services
Antriksh Narang
5 years+ Experienced Dev (Specially in Web Development), can help in python, javascript, react, next.js and full stack web dev technologies.
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
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 do text files upload fine but images get corrupted?
Text files survive UTF-8 encoding because they're already text. Binary files (images, PDFs, ZIPs) contain byte sequences that are invalid UTF-8, so encoding them as strings destroys the data. Always handle binary files as Buffers.
How can I tell if corruption happens during upload or download?
Check the file directly in your storage dashboard (S3 console, Supabase dashboard). Download it from there. If it's corrupt in storage, the upload is the problem. If it's fine in storage but corrupt when downloaded through your app, the download handler is the issue.