How it works

Your files never leave.

Most converters work by uploading your file to a server somewhere, converting it there, and sending it back. useformat doesn't do that. The conversion happens inside your browser, on your own device — the file is never sent anywhere.

Your device · nothing leaves this box
📄
Your file
picked from your device
→
⚙️
WebAssembly engine
runs in your browser tab
→
✅
Converted file
saved straight back to you
✕ No upload · ✕ No server · ✕ No tracking

What's actually happening

useformat loads small conversion engines — the same battle-tested tools used everywhere, like FFmpeg for audio and video — compiled to WebAssembly so they run directly in your browser. When you drop in a file, the engine processes it locally and hands you back the result. No round-trip to a server, no queue, no waiting on an upload.

✓ Completely private. Your files are never uploaded or stored. There's no server to send them to in browser mode — they stay in your browser's memory and are gone when you close the tab.
✓ Works offline. Once the page has loaded, you can disconnect from the internet entirely and conversions still work. Try it.
✓ No account, no limits, no ads. Nothing to sign up for, no daily caps, no banners. It's free because there's almost nothing for me to host.
✓ Instant start. No queue and no upload wait — the moment you drop a file, it begins. The first audio/video conversion downloads the engine once (~30MB), then it's cached for next time.

When would I ever need the server?

A few formats need heavy native tools that simply can't run in a browser — things like Word and PowerPoint documents and certain ebooks. For those, useformat uses a server mode: the file is sent to a small server I run, converted there, and the result sent straight back to you — then both the upload and the result are deleted within minutes. Server mode is always clearly labelled, and browser mode stays the private default for everything that can run locally.

Everything that can run on your device still does — browser mode is the default, and server mode only kicks in for the formats that genuinely need it.

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