The sync protocol does indeed calculate the delta between peers and efficiently catches both sides up.
The backends you see are the ones I use, but the API is a binary blob key value store with range queries: supporting other stores should be straightforward.
Authentication isn’t exactly left as an exercise to the reader but is an area of active work. I would say securing access to a URL via whatever mechanism you’re used to should be fine for client server applications and peer to peer folk seem to mostly have their own ideas.
The backends you see are the ones I use, but the API is a binary blob key value store with range queries: supporting other stores should be straightforward.
Authentication isn’t exactly left as an exercise to the reader but is an area of active work. I would say securing access to a URL via whatever mechanism you’re used to should be fine for client server applications and peer to peer folk seem to mostly have their own ideas.