Service that sync ebooks from all platforms

I've managed to accumulate a scary amount of ebooks over the last ten years and would like to make a dent in them, but keep trying and deleting some that I bought for the 'wrong' reasons. (The same wrong reasons we all have stacks of unread books all over the house... some of us, anyway.)

So that means kobo, kindle, smashwords, google play, as well as the DRM free ones! would have to cohabitate in one application, even if clicking on a book takes me out of the app.

Since my kindle library specifically changes frequently, I was wondering if there was a platform that does one thing: automatically checks what books are in what libraries.

I've begun this process on librarything, but keeping up with it is daunting. My ebook library here is years out of date. I don't need it to push books to all platforms like an ebook version of 'movies anywhere' or even have them available to download from the cloud. All I want is an updating catalogue that I can link all my ebook accounts to.

I've downloaded calibre and will see if I can do anything like that with it, but initial looks say probably not simply.

Thanks for your help!

Calibre might work - are all your ebooks on one device? If so whenever you connect that device to calibre it will check your library, but I'm not sure it updates a catalogue available offline. You can add the books on the device to the calibre library very easily. I'm not sure if you can then 'do' anything with the calibre library though.

Thanks for replying, reading_fox! I don't have all my ebooks on one device because its simply too many. I was hoping to avoid doing it manually because kindle doesn't work easily with other apps (calibre included) unless you download your whole library. Of course I can do that, and may have to, it just wasn't my first choice.