Spine is an iPhone audiobook player for a library the listener already owns or hosts. It can play local files and connect to supported sources such as Torbox, Audiobookshelf, Grimmory, and BookOrbit; compatible folders can also be opened through Files. Playback controls, chapter navigation, bookmarks, sleep timer, variable speed, and progress tools live on each book's detail page, with downloads available for offline listening. Optional Hardcover linking can sync reading progress and completed books, while Apple Intelligence can create on-device recaps and summaries on supported devices. The developer says the app is free with no ads, subscriptions, or in-app purchases and no Spine account to create. The developer privacy page says library and listening data stay on-device or in the user's iCloud, but a limited first-party feature-usage snapshot is sent to CloudKit. The app is designed for iPhone and requires iOS 26.0 or later; iPad and Mac are not currently supported. DRM-protected Audible or Libby books cannot be imported into third-party players.
