here’s been a lot of talk in the .NET community about Sinatra clones, namely Nancy and Nina in recent times but there are several others as well. Unfortunately, all these frameworks are missing the underlying reason that Sinatra is awesome and that is Rack. Sinatra packs a hell of a lot of functionality yet weighs in at 1198 lines of code including documentation. The main reason for that is the fact it is building on top of Rack which has allowed the authors to concentrate on creating a framework without having to worry about the details of dealing with server requests. So what is Rack, why you should care and why does it matter to you as a .NET developer.