We've been working on this for the past three months. I started this project because many clients I work with (as part of my consulting gigs) have switched to Micro Services and needed an API gateway in front of them (to do response aggregation, rate limiting etc). There are options out there like Kong, but some of them prefer a simpler (and free) tool extensible with JS. That's how Prism was born.
Aside of regular API gateway features, some capabilities in Prism are unique. For instance, Prism can receive messages on Redis channels and forward them to specific WebSocket clients. This allows multiple services to asynchronously send messages to WebSocket clients.
Prism is in Beta but good enough to start trialing with. Over the next few weeks, I plan to add more tests and improve the documentation. In particular, the documentation around WebSockets needs more attention.
Happy to handhold anyone who wants to try Retransmit. If you run into problems, please file an issue on github.