Recently, upgraded rails to rails 5, since then (ChatController < WebSocketRails::BaseController ) chat controller which inherits webscoket base controller cannot be autoloaded in development. In production , there is no issue since eager load works fine. Verified with websocket demo too. It fails with rails 5. Tried manual autoloading, even then it fails. I read this bigbinary article( http://blog.bigbinary.com/2016/08/29/rails-5-disables-autoloading-after-booting-the-app-in-production.html ) that rails 5 removed autoloading in production, but not in development. Any ideas?