"Your files never leave your device" is easy to write and hard for a visitor to check. You do not have to trust it. Every modern browser lets you watch exactly what a page sends over the network, and the test takes about two minutes.
Method 1: watch the Network tab
This is the most reliable check.
- Open the tool page, then press F12 (or Ctrl+Shift+I, Cmd+Option+I on a Mac) and open the Network tab.
- Click the clear button so the list is empty, and turn on "Preserve log" if you see it.
- Use the tool: choose a file and run the conversion.
- Look at the requests that appear. A tool that uploads your file shows a POST or PUT request whose "Size" or request payload is about as large as your file, usually to an /upload or /api address.
- A client-side tool shows nothing like that. You may still see requests for scripts, fonts, images or ads; those are the page itself, not your file.
Method 2: go offline
Load the tool page, then turn off your Wi-Fi or enable "Offline" in the Network tab and use the tool again. If it still works, the processing is happening on your device. Some tools legitimately download a library the first time you use a feature, so load that feature once before going offline.
What you will still see leave your browser
Checking honestly means knowing what is normal. Loading any web page sends a request to the host. ToolGalaxy also loads a few libraries from a public CDN (for example the PDF library used by the PDF tools) and, after the page has loaded, Google AdSense ads. None of these receive the file you are working on. Our privacy-first page lists exactly what is requested and why.
Red flags
- A progress bar that says "uploading" or "processing on our servers".
- Large POST requests to the site's own domain while you convert a file.
- Features that clearly need a server, such as OCR in the cloud, e-mailing a result, or a link that lets someone else download your output.
- A "free forever" claim next to account sign-ups, file history or cloud storage.
If you want a quick test, try the PDF Compressor below with the Network tab open. You should see the page assets load, and then nothing as the compression runs.