Almost every free PDF tool claims to respect your privacy, usually with a badge declaring "Files deleted after 1 hour!" But if a file is deleted after an hour, it means it was stored on their server for an hour. If you're dealing with sensitive data, that's 60 minutes too long.
The Difference Between "Auto-Delete" and "No Upload"
There is a massive difference between a company promising to delete your uploaded file and a tool that never uploads your file in the first place. The latter is known as a client-side tool. It uses your web browser to do the processing locally on your computer.
Unlike tools like iLovePDF or Smallpdf, Flipp processes everything locally in your browser using secure open-source libraries like pdf-lib — your files never leave your device.
How to Verify a Tool is Truly Private
You don't have to take a website's word for it. You can verify if a tool is uploading your files by checking your browser's network activity.
- Open the PDF tool you want to test.
- Right-click anywhere on the page and select "Inspect" (or press F12) to open Developer Tools.
- Click on the "Network" tab.
- Drag and drop a PDF into the tool.
- Watch the Network tab. If you see a large file being sent (a POST request) that matches the size of your PDF, the site is uploading your data to their server. If the Network tab stays quiet or only shows tiny, unrelated requests, the tool is processing the file locally.
By testing tools yourself, you can ensure your confidential documents remain exactly that—confidential.
