Yeah, it's a pretty fascinating architecture. I already have a side project called AppDeck where I've been buliding out a WebDAV server and a suite of HTML apps that know how to save modified copies of themselves back to the server. I've been using it for a couple of years, and the suite is growing - tools, apps, games, etc.

My son had written a game like this called "Quantum Chain" that had basic leaderboard functionality. That was the first app we ported: the platform injects the webcdx.js shim, and we update Quantum Chain to post messages to it when someone finished a game with a high score. This is replicated out to the relays the same way every message in the group chat is. When the app fires up, Delta/ArcaneChat replay all messages that are typed for that app back to it, and it restores it's state that way. There's some localstorage caching to make this a bit more efficient as the stream grows.

So it's a bit like several services reading off the same kafka stream to stay in sync.

I've since ported over (and massive improved) my implementation of KenKen, which also has leaderboards. I then took on realtime gameplay: a card game my family likes called "Shithead" that supports 2-6 players. I built a first version in about 6 hours, and I'm still working out session management (so folks can join and leave games and everything syncs properly). Still a couple of edge cases to fix, but overall, it been trivially easy to bring over webapps to the platform that already exist, and a few hours of effort to create a new one.

I'm pretty thrilled with the whole ecosystem, as it gets me away from all the BS the companies have layered on top of the basic "Apps with Friends" experience ArcaneChat offers.