ZenConvert

Convert files locally — no uploads, ever.

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June 7, 2026 I built a file converter that runs entirely in your browser — no uploads, ever

Every popular file converter - CloudConvert, Convertio, online-convert - uploads your files to their servers. Your photos, videos, documents sit on someone else's machine, even if briefly.

ZenConvert works differently:

  • Images processed via HTML5 Canvas API

  • Videos processed by FFmpeg compiled to WebAssembly - runs entirely in your browser tab

  • Nothing touches a server. Ever.

What that means practically:

  • Convert sensitive documents without worry

  • Works offline once loaded

  • 50+ image formats, 50+ video formats

  • Batch conversions, DPI settings, EXIF stripping, video trimming

Advanced Mode unlocks formats most people have never heard of -NASA FITS, Amiga IFF, Kodak Cineon, PlayStation STR. Formats spanning 1981 to 2024.

Pro plan starts at $5/month for unlimited conversions and larger file sizes.

Would love feedback, especially from anyone who's worked with WASM or FFmpeg in the browser before.

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Every file converter uploads your files to some server. I wanted one that never does. ZenConvert runs FFmpeg via WebAssembly - entirely in your browser. No uploads. No servers. Just local processing.