shermanp:

 

Calibre-web actually implements the Kobo sync protocol to some extent. I don't know how well it works lately, I briefly tried it, but its implementation didn't really suit my reading style.

 

Kobo's have a browser. It's experimental, and pretty awful to use in practice. If you don't mind plugging in via USB, Kobo devices have extremely good support in Calibre.

 

Although it's been a since I last worked on it, Kobo-UNCaGED is an implementation of the "Calibre Companion" wireless protocol, which should still work.

 

I actually have a half finished OPDS client I've been working on, although I've been busy with other stuff the past couple of months, so no guarantee I'll ever finish it.

 

I hope this helps!

 

yeah, my calibre is not really accessible via USB (windows server hyperv with calibre on a Linux vm).  So I need to either email it, use a browser or an opds client.   Though yes it does have s Kobe sync, but I don’t know what that is.