Oh, can't derive IDL from JS, because no static types. Could add type hints, or type inference (partial), or just an actual IDL. Still easy to use!

JS (and py) devs aren't keen on static types... might be a hard sell.

Java seems a perfect fit: static typed, adopted. Also cloud-like "application servers". But already has CORBA and IDL's and serialization - just not popular (why not? maybe goes back to our previous comments) What advantages do you have over that? Uncool, but might be an easy sell.

BTW: There's something tantalizingly puzzling about the whole "JS static types for RPC" thing... not dynamic, not REST... Big picture is not yet clear to me.

REST is popular (eg http://swagger.io to generate APIs and docs); static types mismatch JS, but help RPC (very interesting and popular thread from 3 days ago on "statically linking" microservices - enterprise people concerned https://www.reddit.com/r/programming/comments/3k8sb2/how_we_... )