Are online PDF tools safe? How to tell whether your file is uploaded
When you drop a PDF into an online tool, where does it go? Some sites send it to their servers to process it, which means your document, and whatever is in it, leaves your device. For a contract, an ID or a bank statement, that is worth knowing before you click.
Two very different kinds of tool
Server-based tools upload your file, process it on their computers, and let you download the result. The file passes through, and may be stored on, machines you do not control.
Browser-based tools do the work on your own device using code that runs in the page. The file is opened by your browser and never sent anywhere.
How to check for yourself
- Watch for an upload bar. A tool that uploads usually shows one, and takes longer on big files.
- Turn off your internet after the page has loaded and try the tool. If it still works, your file is not being sent anywhere.
- Open your browser developer tools (usually F12), go to the Network tab, and run the tool. An upload shows up as a large request carrying your file.
- Read the privacy policy for words like "we store" or "deleted after 24 hours". A tool that never receives your file has nothing to store.
What to be careful with
- Passports, ID cards, bank statements and contracts deserve the most caution.
- Free tools that ask you to create an account or give an email address for a simple task are worth a second look.
- Files that go through a server can be logged, cached or breached, even when the company means well.
How this site works
Every tool on this site runs in your browser. The code is downloaded with the page, and your files are read by your browser and processed on your device. There is no upload step and no server that receives your documents, and you can confirm that with the checks above.
It also keeps working with the connection off once a page has loaded, which is the simplest test of all.
Limits of the approach
Working on your own device means very large files depend on your memory, and some jobs, such as recognising text in scans, are slow because your own device does all the work: a page takes seconds, not milliseconds. That is the price of keeping the file with you, and for most people it is worth it.