ConvertKing
Convert files in your browser. Zero uploads, 100% private.
6 followers
Convert files in your browser. Zero uploads, 100% private.
6 followers
ConvertKing is the only file converter that works 100% in your browser using WebAssembly. Your files never touch our servers. 🔒 Privacy First: Files never uploaded, all processing happens locally ⚡ Lightning Fast: Instant conversions powered by WebAssembly 🆓 Completely Free - Unlimited conversions, no subscriptions 🎯 All Formats - Video, Audio, Images, Documents, E-books 🚫 No Sign-Up - Start converting immediately 💻 Works Offline - Once loaded, works without internet
I'm excited to launch ConvertKing - a file converter that actually respects your privacy!
The problem:
I needed to convert a video at 2 AM. Every online converter made me upload my files to their servers, had file size limits, required sign-up, or bombarded me with ads. I thought: "It's 2026. Why are we still uploading files to convert them?"
The solution:
ConvertKing runs FFmpeg (industry-standard conversion tool) directly in your browser using WebAssembly:
Your files never leave your device - Everything happens locally
Completely private - We literally can't see your files
100% free & unlimited - No subscriptions, no file size limits
No sign-up needed - Just drag, drop, and convert
Supports: Video (MP4, MOV, GIF), Audio (MP3 extraction), Images (JPG/PNG/PDF), Documents (PDF ↔ Word)
My journey:
Started with a server-based approach but hit issues with hosting costs ($20-50/mo), privacy concerns, and upload limits. Discovered FFmpeg.wasm and rebuilt everything client-side. Now it's $0 hosting, complete privacy, and instant downloads.
What's next:
Batch conversion
More formats (EPUB, MOBI, FLAC)
Browser extension
Quality presets
I built this to prove that useful tools can be free without exploiting users or sacrificing privacy.
Try it out! What formats would you like to see next?
Looking forward to your feedback! 🚀