If we want to talk about the minutia. None of these are "real time". Heck even the universe puts a limit on how quickly events can happen. We can look at the li

If we want to talk about the minutia. None of these are "real time". Heck even the universe puts a limit on how quickly events can happen. We can look at the light from galaxies so far away that we see the galaxy billions of years into it's past. So nothing can be instantaneous. However, I would say real time generally means acceptable latency or acceptable time reach to consistency. Although, I generally think of real time more along the lines of embedded systems. Moreover, the word server-less really irks me. It's not server-less. You just don't have to manage the server or really interact with the server software that much. It's still a server.