ZeroUpload is a free file converter with one defining principle: your files never leave your device. Every conversion happens locally, inside your own web browser, using technologies like the Canvas API and WebAssembly.
Why we built it
Almost every "free online converter" quietly uploads your files to a remote server to do its work. For private documents and personal photos, that is an unnecessary risk. We believed there was a better way — and modern browsers are now powerful enough to convert files without sending them anywhere.
How it works
When you drop a file into ZeroUpload, it is read from your device into memory, transformed by an in-browser engine, and returned to you as a download. Nothing is transmitted across the internet. You can prove this yourself: start a conversion, disconnect your internet, and watch it keep working.
What we offer
Free, unlimited, private file conversion with no account required. Because the work runs on your device, there are no server costs — and therefore no paywalls, no queues, and no limits beyond what your own device can handle.
Get in touch
Questions, feedback or a format you'd like us to support? Reach us at hello@zeroupload.app.