Though Ruby world is not new to ‘async’, there are many famous libraries in Ruby which are event-driven like eventmachine and celluloid but ‘async’ is not as main stream in Ruby as it is in other communities like Node.js is quite popular in JavaScript world and RxJava is new hot topic in Android eco system. https://medium.com/@gauravbasti2006/lets-keep-our-promise-in-ruby-e45925182fdc