Automated emails to watch an intro video and then do a CCAT aptitude test and Ruby / MySQL / Redis related multiple choice test with 36 questions. You have to go very fast on both, but the ruby questions are quite wordy. Almost every question on the latter is formulated as a trick in one way or another even if the answers for some might be 'obvious'. I would say that a majority of them are exceedingly esoteric. They appear to be looking for autistic savants only. Good luck, I guess.