The problem with sync engines is needing full-stack buy-in in order for it to work properly. Having a separate backend-for-frontend service defeats the purpose in my mind. So what do you do when a company already has an API and other clients beyond a web app? The web app has to accommodate. I see this as the major downside with sync engines.

I've been using `starfx` which is able to "sync" with APIs using structured concurrency: https://github.com/neurosnap/starfx