What we collect
Nothing. Margin has no accounts, no sign-in, no analytics, no advertising, no tracking, and no third-party SDKs that report on you. The developer cannot see your library, your notes, or how you use the app.
Where your data lives
Your books, collections, highlights, notes, bookmarks, reading progress, and display name are stored on your device.
If you are signed in to iCloud, this data also syncs through your own iCloud account using Apple’s CloudKit, so it is available on your other devices and survives replacing your phone. It is held in your private iCloud database. The developer has no access to it, and it is covered by Apple’s privacy policy.
If you are not signed in to iCloud, Margin keeps everything on your device and does not sync.
Services Margin contacts
Margin talks to the services below only when you use the feature that needs them. None of them receive an identifier for you from us.
- Open Library and Google Books — when you search for a book or scan a barcode, Margin sends the search text or the ISBN to look up the title, author, and cover. It does not send your library, your notes, or anything identifying you.
- OpenAI — only if you choose to use the AI reading companion. The feature is off until you enter your own OpenAI API key in AI Settings, and Margin never ships a key of its own. When you send a message, the passage under discussion, your related highlights and notes, and your message are sent to OpenAI under your API key, subject to OpenAI’s policies. Your key is stored on your device and is never sent anywhere except to OpenAI. If you never enter a key, Margin never contacts OpenAI, and you can clear it at any time.
Camera and photos
Margin uses the camera when you scan a book’s barcode or photograph a page to capture a passage. Images are processed on your device using Apple’s Vision framework. Photographs of pages are not uploaded anywhere and are not saved to your photo library — only the text you choose to keep is stored, in your library.
Files you import
PDFs and EPUBs you import are copied into Margin’s own storage on your device so the app can open them later. They are not uploaded.
Children
Margin is not directed at children under 13 and does not knowingly collect information from them.
Deleting your data
Deleting the app removes everything stored on your device. To remove synced data, delete Margin’s data from iCloud in Settings → your name → iCloud → Manage Account Storage.
Changes
If this policy changes, the date at the top of this page will change with it.
Contact
Questions about privacy: contact@caracalcw.com