Calibre-Web

Calibre-Web is a browser-based front end for a Calibre e-book library, giving you a clean reading interface on top of the books and metadata Calibre already manages. It supports browsing by author, series and tag, reading formats in the browser, OPDS and RSS catalogs for compatible readers, and can sync progress to e-reader devices.

Readers use it to reach their library from a phone or tablet without installing Calibre itself, and it can be added alongside an existing Calibre library.

Since the books and the database sit on your own storage, your reading habits stay private, there is no per-user charge for the interface, and restoring the Calibre data folder brings the catalog back intact.