Short version: your PDF stays on your device.
Tall PDF Slicer reads your PDF and builds the new one inside your browser. Your file is not uploaded, sent to a server or kept by this site. When you close or refresh the page, it is gone from the page.
The page remembers a few settings in your browser so you do not have to pick them again: the page size you chose, Automatic or Manual mode, and the zoom level. This stays on your device and is not sent anywhere. This site does not set cookies of its own.
The fonts and the open-source code libraries that read and build PDFs (pdf.js and pdf-lib) are served from this site itself, so your browser does not fetch them from anyone else. The only outside service the page talks to is the contact form, and only when you send a message.
This site is hosted on Cloudflare, which can count visits for us (page views, the country a visit came from, which page was opened) using its privacy-focused web analytics. It does not use cookies and does not follow you across other sites. We do not run any other analytics and the site shows no ads. If that changes, this page will be updated first to say what is used and how you can opt out.
The Contact form sends us your message, the topic you chose, and your email address only if you type one in. We use it to read and reply to you, and we do not share it or add it to any list. The message is delivered by a third-party form service. Please do not put anything private in it, and never include the contents of your PDF.