There’s no way you could implement this in 10kb of rust. It takes massive advantage of javascript’s dynamism to work. Also, I’m pretty sure ts / js are vastly more popular languages than rust. I suspect this will get a lot more use because it’s typescript.

Yes, pretty much. Just interfacing between the JS app and the Wasm RPC implementation would take more code than the entire RPC implementation in TypeScript.

Also, the audience of this library is very specifically TypeScript developers. If your app is Rust, you'd probably be happier with Cap'n Proto.