Thanks for your response it took me a while to respond because I am still trying to fully understand the implementation you suggested. My understanding is that:

1. I need to run a server on the Rust client (CLI) that would take user commands and convert it to a JSON payload to be sent to the Rascal backend
2. I need to also run a server on the Rascal backend that would accept request from the client, marshal the payload sent by the client into a Rascal ADT and use it to call a Rascal function then convert the result into a JSON payload to be sent back to the server.

I assume this setup would work for any client app (Java, Python etc). I will look at the util::Webserver api to see how to spawn a server in Rascal if there are any examples I will be extremely glad if you can point me to it. I already have some experience working with lang::json::IO. Thanks once again this is very useful.