How to check that a PDF tool does not upload your file
Plenty of free PDF sites say your files are safe. You can verify it in a couple of minutes with tools already built into your browser.
The quick test
- Open the tool page, for example Compress PDF.
- Open your browser’s developer tools. On desktop Chrome, Edge or Firefox, press F12, or right-click the page and choose Inspect.
- Click the Network tab.
- Clear the list, then choose a PDF and run the tool.
- Watch the list. You are looking for a large request that sends your file out, typically a POST to a server.
What you should see
On a tool that really works on your device, you will not see your file being sent. You may see small requests for the page’s own scripts or fonts, loaded before or after, but not a request carrying your document.
The offline test
- Load the tool page.
- Turn off your internet, or switch on airplane mode.
- Choose a file and run the tool.
If it still works, the processing is happening on your device. Note that some tools load extra scripts the first time they run, so try the tool once online first.
What this does and does not prove
It shows what your browser sends while you test. It does not prove anything about other sites, or about future changes to a page. Repeat the check on any tool you use with sensitive documents.
Why it matters
IDs, payslips, contracts and transcripts are sensitive. A tool that never uploads them removes a whole category of risk.