FBReader

About

FBReader for Mac OS is an ebook reader that works on Mac OS 10.14 and higher, on both Intel and Apple Silicon. You can install it from the Mac App Store or download the package from the FBReader website. The App Store version differs slightly, because it handles ebook purchases in a way that meets Apple's guidelines.

The app opens ePub files, both unencrypted and protected with Readium LCP. It also supports fb2, mobi, HTML, RTF, and plain text. FBReader uses its own book parser and rendering engine, which the site describes as lightweight, fast, and highly customisable.

FBReader is available on other platforms too, including Windows, Linux, Chrome OS, Android, and iOS. The site also offers an FBReader SDK for developers who want to build their own ebook reader.