I’ve got BookOrbit and Audiobookshelf both going. They both can be hosted securely (locked down compose file with read-only, non-root user, etc.) and use Postgres as their DBs, both key features.

I added in BookOrbit to try since it has kobo sync and koreader sync that Audiobookshelf lacks.

I moved books from Audiobookshelf to get BookOrbit going and there was a learning curve to get the UI to do it optimally for me, but I eventually got it to work for me. BookOrbit has the ability to write metadata to the files themselves, which most things lack. Very nice for portability.

There’s a folder BookOrbit imports from and you can set it to populate metadata automatically - seems strongly built for an automated library system.

Both have been very stable. I’d say BookOrbit is the better one - and it supports audiobooks too. Audiobookshelf handles multiple libraries (like books and comics) in a clunky way (have to switch between them like they’re completely different silo’d libraries - much like how Calibre handles them). BookOrbit has them separated but easy to see they exist and you can mix and match them in a collection or something. Better way to handle it.

I use the desktop application Calibre to convert books as needed, but BookOrbit will automatically generate kobo epubs from epubs when syncing so I need not worry about kepub prep.

Lastly, I chose BookOrbit to try over others because Grimmory needs a ton of RAM, Kavita had features behind a paywall, some other one is comic-focused, and the Calibre web iterations give off the vibe of a lot of tapes the inside to make them work; I had big doubts Calibre Web Auto would be able to be run non-root and read-only. Chose Audiobookshelf originally because of the Calibre mess and other options didn’t exist or were much less established.