See for yourself.
We say your files never leave your device. Here's the live network monitor that proves it — running on this very page.
Verify in 30 seconds
- 1
Open DevTools
⌘ ⌥ I on Mac · Ctrl Shift I on Windows / Linux
- 2
Click the Network tab
Make sure recording is on (the red dot top-left). Optionally click "Clear" to start fresh.
- 3
Click "Run a sample compression" below
A tiny sample PDF is generated and compressed entirely in your browser.
- 4
Watch the Network tab
Zero new requests during compression. No upload. Confirmed by the browser itself.
DevTools — Network
No network activity captured yet.
Resources from this page will appear here.
The panel above reads from PerformanceObserver — the same browser API that powers Chrome DevTools' Network tab. If we uploaded your file, you would see it appear here in real time. We don't.
Why DevTools is enough proof
Every browser ships with a built-in network inspector that shows every HTTP request the page makes — including ones a malicious page might try to hide. There's no way for a page to send a file out of your device without showing up in this panel. If we ever upload your file, you would see it. We don't.
This page also runs the same panel in real time, so you don't have to take our word for it on the other tools — every compression page on this site behaves identically.
See the code yourself
The compression engine is open source. Read it, audit it, fork it. If you find a security issue, please report it before disclosing publicly — see the SECURITY.md in the repo.
Ready to compress something for real?