Twitter: From Ruby on Rails to the JVM

Twitter, historically, has been one of the Internet's largest Ruby on Rails website. To support the volume of traffic that comes along with that, Twitter has jumped through many hoops: from re-architecting the way it uses Rails to building and running its own custom Ruby interpreter. To help us focus on our core mission of "real-time" we've undergone a transition and are currently running portions of our core logic in the JVM. This has had a side effect of not just improving our efficiency, scalability, and reliability, but it has also given us an opportunity to gain much more flexibility in terms of language and overall architecture.