Scytale · Privacy

Scytale Privacy Policy

How the Scytale app for iPhone, iPad and Mac handles your information.

Last updated October 5, 2026

The short version

  • Scytale does not collect, sell or share your information. S4 Solutions has no server for this app and cannot see your data.
  • There are no accounts, no ads, no analytics and no tracking in the app.
  • Your books, reading positions, highlights and statistics stay on your devices and, if you turn on iCloud Sync, in your own iCloud account.

What the app stores, and where

  • On your device: your book files, library, reading positions, highlights, notes, bookmarks, saved words, reading statistics, goals and settings.
  • In your iCloud, if you turn on iCloud Sync: your library records, reading positions, highlights, notes, statistics, goals and server addresses, in your private iCloud database through Apple's CloudKit. Book files you imported yourself are not uploaded.
  • In the Keychain on your device: the passwords for your servers and your Readwise token. These are not synced.

When Scytale connects to the internet

Scytale makes a network request only for a feature you use. Each service below sees your device's IP address, as any website does, and handles it under its own privacy policy.

  • Your own servers. If you add a Calibre server or an OPDS catalog, Scytale connects to the address you entered to browse and download books and, for Calibre, to sync reading progress, status, rating and notes.
  • Book details and covers. For books you import yourself, Scytale looks up details and covers at Open Library and Google Books, sending the book's ISBN, or its title and author. Books from a Calibre server are not looked up.
  • Readwise. If you enter a Readwise token and export highlights, those highlights are sent to Readwise.
  • Natural voices. If you choose to download the natural read-aloud voices, the files come from Hugging Face. Speech is generated on your device; the text of your books is not sent anywhere to be read aloud.
  • Translate. If you select text and tap Translate, Scytale shows Apple's translation sheet. iOS sends the selected text to Apple to translate it, unless you have chosen on-device translation in iOS Settings, and tells you so the first time. Apple handles it under Apple's privacy policy.
  • Purchases are handled by Apple.

Who can see your data

  • You.
  • Apple, which hosts iCloud storage under Apple's privacy policy, if you use iCloud Sync.
  • Not S4 Solutions. The data is on your devices and in your iCloud account, not ours, and we have no way to access it.

Children's privacy

Scytale does not collect personal information from anyone, including children.

Keeping and deleting your data

  • Removing a book in Scytale deletes its file and highlights from the app.
  • Deleting Scytale from a device removes the data stored on that device.
  • Data in iCloud can be deleted in iOS Settings → [your name] → iCloud → Manage Storage (or Storage) → Scytale.
  • Progress and notes written to your Calibre server stay in your Calibre library until you remove them there.

This website

This policy covers the Scytale app. The s4solutions.ai website uses privacy-friendly analytics to count visits; that is separate from the app, and the app sends nothing to this website.

Changes and contact

If this policy changes, we will update this page and the date above. Questions or requests: info@s4solutions.ai, S4 Solutions, LLC, Atlanta, Georgia.