* portable: runs on embedded devices (Cervantes, Kindle, Kobo, PocketBook), Android and Linux computers. Developers can run a KOReader emulator in Linux and MacOS.
* full-featured reading: multi-lingual user interface with a highly customizable reader view and many typesetting options. You can set arbitrary page margins, override line spacing and choose external fonts and styles. It has multi-lingual hyphenation dictionaries bundled into the application.
* integrated with calibre (search metadata, receive ebooks wirelessly, browse library via OPDS), Wallabag, Wikipedia, Google Translate and other content providers.
* optimized for e-ink devices: custom UI without animation, with paginated menus, adjustable text contrast, and easy zoom to fit content or page in paged media.
* and much more: look up words with StarDict dictionaries / Wikipedia, add your own online OPDS catalogs and RSS feeds, online over-the-air software updates, an FTP client, an SSH server, …