Airbrake gem fails when your rails sessions are disabled

If you experiment

undefined method `data' for nil:NilClass

after installing Airbrake gem and you have disabled your rails sessions ( for example with the session_off gem ) This is because airbrake read the session.data property to send them to the server. Since you disabled Session's , your controller's session returns nil. I submitted a fix to airbrake, if you can't wait you can source your aibrake gem from my github repository Edit : My branch has been merged in master, you can now rely on master.