Watch it not upload your file
Every converter claims privacy in its footer. This one lets you check.
Every file converter has a line about privacy somewhere near the footer, and there is no obvious way to tell the honest ones from the rest. This page does not ask you to take it on trust. Convert something and watch the browser’s own record of what left this device — the same accounting the Network tab uses — counted as the work happens.
What you are looking at
- Every request the page has made, from the browser itself.
- The bytes each one transferred.
- A count taken from the moment your conversion starts.
- It stays at zero, because there is nowhere here to send a file.
Why the number is trustworthy
- It comes from the browser’s performance timeline, not from this code.
- Your own Network tab shows exactly the same requests.
- You can also disconnect from the network and keep converting.
- A converter that needed a server could not do that at all.
Questions
How do I know a file converter is not uploading my files?
Open the Network tab in your browser’s developer tools and convert something. You will see the page and its code load, and after that nothing carrying your file. The stronger test is to disconnect from the internet after the page has loaded: anything that still converts was never using a server.
What are the requests it does show?
The page, its stylesheet and code, and for video or audio the WebAssembly build of FFmpeg. Those are programs being downloaded to you, which is the opposite direction from your file being uploaded, and they are listed rather than hidden because pretending a 31 MB download did not happen would undermine the point.
Could a page hide an upload from this?
Not from the browser’s own timeline, which is where these numbers come from. That is also why the honest version of this page is possible at all: a converter that uploaded your file would be publishing the evidence.