~/answers

Is it safe to compress a PDF online?

It depends on where the file goes. Most online compressors upload your PDF to their servers to process it. A tool that runs in your browser compresses it on your own device, so the file never leaves it.

What happens with an upload

An upload-based site copies your PDF to its servers, processes it there and sends back the result. Reputable services delete files after a while, but you are trusting their policy, their security and anyone they share data with. For contracts, medical forms, bank statements or anything with personal details, that is a real risk.

How to tell where your file goes

• Read the privacy policy for words like “uploaded”, “stored” or “deleted after”.
• Open your browser’s developer tools, go to the Network tab and run the tool. If the size of your file shows up as an upload, it left your device.
• Try it offline: a tool that runs in the browser keeps working with the connection off once the page has loaded.

Compress a PDF without uploading it

Snowkit’s PDF compressor runs in your browser. The file is read and compressed on your device, and you can check the Network tab yourself. It is free, with no sign-up and no watermark.