It doesn't try to solve the same use cases that Calibre does, but I built an open source (EPUB only) manager / reader / statistics tracker called AnthoLume [0].

It doesn't try to solve the same use cases that Calibre does, but I built an open source (EPUB only) manager / reader / statistics tracker called AnthoLume [0]. It mostly stemmed from me reading in KOReader [1] on my Kindle, and not having the ability to sync the progress to my iPhone / iPad. It's got metadata matching, support for multiple users, and statistics tracking which allows me to have a "Leaderboard" that shows how fast you read (words per minute). Fun competition between my wife and I (that I'm 100% losing). It's a Progressive Web App and utilizes a Service Worker to support 100% offline reading as well. There's a demo server [2] (creds are "demo" for both user & pass). [0] https://gitea.va.reichard.io/evan/AnthoLume https://gitea.va.reichard.io/evan/AnthoLume [1] http://koreader.rocks/ http://koreader.rocks/ [2] https://antholume-demo.cloud.reichard.io/ https://antholume-demo.cloud.reichard.io/