Calibre-Web

Calibre-Web puts a clean, browsable web UI on top of a Calibre database. If you already maintain a library in Calibre, this is the fastest way to read it from any browser, send books to an e-reader, and share it with family accounts.

It depends on the Calibre library format rather than replacing Calibre itself, so it works best as a companion: Calibre for management, Calibre-Web for access. It is light enough to run anywhere.

Choose it if Calibre is already your source of truth; look at Kavita if you are starting fresh.