Does PrivaConv make any network requests at all?

Yes — the page itself, and the FFmpeg WebAssembly encoder the first time you compress a video. Those are downloads to your browser, not uploads of your file. After they are cached the tool works with the network off.

Why should I verify instead of trusting the claim?

Because the claim costs nothing to make. "No upload" appears on sites that do upload, and you cannot tell them apart from the marketing copy. The check takes under a minute and works on any site.

Verify it yourself

Open DevTools, clear the Network panel, convert one file, and sort by size. If your file were being uploaded, a request roughly the size of your file would appear. Then turn the network off and convert again — a tool that needs a server cannot.

"Your files never leave your device" is on this site, and on plenty of sites where it isn't true. It costs nothing to write. This page shows you how to stop taking anyone's word for it, including ours.

The one-minute check

Open the Network panel. F12 on Windows and Linux,Cmd+Option+I on a Mac. Choose the Network tab.
Clear the log. The circle-with-a-slash button. Now the panel only shows what happens next.
Convert one file. Keep the panel open while it runs.
Sort by size. Click the Size column header. An upload of your file cannot hide here: sending a 40 MB video means a request carrying roughly 40 MB. Downloads of the encoder will appear, and they are the other direction.
Check the method. Uploads are almost always POST orPUT with a request body. Sort or filter on that and look at what is left.

The stronger test: pull the plug

Network inspection tells you what happened. Going offline tells you what is possible.

Load this page normally and let it settle.
Set the Network panel's throttling dropdown to Offline, or just turn off Wi-Fi.
Reload the page. It should still load, from the service worker cache.
Convert a file. It should still work.

A converter that sends your file to a server cannot pass this. There is no cache trick that makes a round trip to a machine you cannot reach.

The first video compression of a session does need the network once, to fetch the FFmpeg WebAssembly encoder. Compress something before going offline and it will be cached.

What you will see, and what it means

Requests this site makes, and how to tell them apart from an upload.
Request	Direction	When
Page, CSS, JavaScript	Download	On load, then served from cache
`ffmpeg-core.wasm`	Download	First video compression only
libheif decoder	Download	First HEIC conversion only
Anything carrying your file	—	Never. That is the whole claim.

Use this on other sites too

Nothing here is specific to PrivaConv. Run the same check on any converter that claims local processing. Some will pass. Some will show your file going out in aPOST while the page says it never leaves your computer. Knowing which is which takes less time than reading the privacy policy.