Background Jobs have become a staple of web development in recent years. They enable us to avoid holding up the request/response flow while the application does something slow, like send emails, or make a ton of inserts that the user doesn’t really care about. In Rails development, we’ve had a myriad of options for queueing for a while now. We all know the popular ones: Resque, Sidekiq, Delayed Job, etc. The upcoming Rails 4.2 release will bestow upon us the glory that is ActiveJob, a unified API for talking to Background job systems.