I am not sure what Realtime means here. But if it means something close to what I used to [1], then REST is a horrible idea. Javascript is not a good idea either.

[1] " Real-time computing (RTC) is the computer science term for hardware and software systems subject to a "real-time constraint", for example from event to system response.[1] Real-time programs must guarantee response within specified time constraints, often referred to as "deadlines".[2] "