I ran all of my Advent of Code[0] solutions in Node.js - there's nothing specific really about running a ReasonML app in Node.js vs the browser. Except you don't need a module bundler for the former. :)

I've also been slowly working on a small CLI app using ReasonML, ReasonReact and react-blessed.

There definitely is a dearth of ReasonML server-side examples, libraries and frameworks, though - especially compared to all the front-end chatter. bs-express[1] is actually quite nice, but hasn't seen much attention from the larger community. I would highly recommend it if it's something you're interested in pursuing.

[0]: https://github.com/Lokeh/advent-2017

[1]: https://github.com/reasonml-community/bs-express

There's definitely activity on the backend, especially with GraphQL, but we don't have any large success stories to report yet. Here's a very cool native-OCaml GraphQL server you can try out today though: https://github.com/andreas/ocaml-graphql-server