How OnePDF handles your files
Your files stay on your device
OnePDF runs inside your browser. When you open a file, it is read by the OnePDF engine on your own computer or phone. Editing, converting, compressing, merging, signing and text recognition all happen there.
Your documents are not sent to our server or to anyone else's.
What is kept in your browser
So you can reopen them from the home screen, copies of the files you open are kept in your browser's own storage on this device, up to 24 of them. They are removed the next time you open OnePDF after closing your browser, or a day after you last opened them, whichever comes first. What you are writing in Create PDF is kept the same way, so a reload does not lose it.
OnePDF can only remove them while it is open in this browser. Until then they stay in your browser's storage on this device, and nowhere else. You can remove any file from the list sooner, and clearing your browser's site data removes everything at once. To keep files longer, sign in: they are kept in your account instead.
What your browser downloads
The site downloads the OnePDF engine and, only when they are needed, fonts for characters your document uses and the text-recognition models. They come from this site and contain nothing about you or your files.
The language of the pages
The first time you open a page of OnePDF that is also written in your language, you are sent to that version. Your language is guessed from the country your internet address belongs to, looked up on our own server in a copy of DB-IP's free country database (IP to Country Lite, CC BY 4.0). Your address is not sent to anyone else for this, and the guess is not stored. Choose a language in the menu at the foot of any page and that choice is kept, in a cookie, instead.
Passwords and certificates
Passwords you type to open or protect a PDF, and certificates you use to sign one, are used on your device only and are not stored or sent anywhere.
If you sign in
Signing in is optional, and no tool needs it. It uses your TensorActivity account at accounts.tensoractivity.com, which tells OnePDF your name, email address and account ID.
While you are signed in, the files you open or save in OnePDF are saved to your account: uploaded to TensorActivity's server, so they are there on any device you sign in to. They count towards your account's storage, which your account page shows. You can keep any file on your device only instead, and delete any file from your account; it is then deleted from storage too.
Files in your account are encrypted on TensorActivity's server, each with a key of its own, and then stored, still encrypted, with Backblaze, a storage company, in its US East region. Backblaze holds only the encrypted files and cannot open them: the keys stay on TensorActivity's server. The server uses them to open your files and send them back to you; TensorActivity does not otherwise look at them. They are not used for anything but keeping them for you.
Files kept in your account are only ever shown to your account. On a shared computer, signing out removes your account's files, and what you were writing in Create PDF, from that browser; the files stay in your account. A file that had not finished saving to your account when you signed out stays in that browser, hidden, until you sign in there again and it is sent.
If you delete your TensorActivity account, your files in OnePDF are deleted too, from TensorActivity's server and from Backblaze, within an hour.
While you are signed in, a cookie on tensoractivity.com holds your first name, so TensorActivity's other pages can greet you, and a second cookie, which scripts on the page cannot read, keeps you signed in to OnePDF. Signing out removes both and signs you out of your TensorActivity account in this browser.