It all depends on your Ruby runtime. If you want parallel threads then you can use JRuby and your threads will run in parallel on the JVM. I've used the Concu

It all depends on your Ruby runtime. If you want parallel threads then you can use JRuby and your threads will run in parallel on the JVM. I've used the Concurrent-Ruby gem to coordinate that[1]. It has copies of some of the Clojure data structures. Otherwise, Ractors the up coming solution for MRI Ruby. 1. https://github.com/ruby-concurrency/concurrent-ruby https://github.com/ruby-concurrency/concurrent-ruby