A few years back I wrote a backend implementation of the LiveView protocol in Typescript (https://liveviewjs.com) and played around with another BunJS-specific implementation (https://hotdogjs.com/). (Also did Java and Go versions but that's another story.)

There isn't an official "protocol" so I had to figure it out by watching the WS traffic and determining how it worked which was fun if not tedious. That said, the more I learned, the more I was impressed by the efficiency and the programming model which felt simpler yet more powerful than SPAs.

I did get to a point where I just got too busy to keep up and over the last couple of years things have changed a bit on the "protocol" side.

But recently (a week ago-ish), I started poking at the old LiveViewJS repo with the help of coding agents. Now that Phoenix is past 1.0 and the JS runtimes (Node, Deno, Bun) have more overlap in terms of APIs and library support, I think it will be more straight forward and frankly easier to get and stay at parity.