One of my favorite apps, Clubhouse.io (the project management solution, not the controversial audio social network), mimics realtime by just having a really, really optimized polling endpoint for the last timestamp the project was touched, then the client refreshes as needed (which would hit cache if you account for distributed systems propagation, if you even need to worry about that). It's an amazingly simple solution and one I'd recommend for anything in B2B modalities.