Rack, a Ruby Webserver Interface Original author(s) Christian Neukirchen Developer(s) James Tucker, Josh Peek, José Valim, Michael Fellinger, Aaron Patterson, Santiago Pastorino, Konstantin Haase Stable release 2.0.3 / May 15, 2017 (2017-05-15) Repository https://github.com/rack/rack Operating system Cross-platform Type Middleware License MIT License Website rack.github.io