I applied through Square's careers page. I got caught in the middle of their hiring break, so my interview process took quite a bit longer than it normally does (a couple of months versus a couple of weeks). As others have said, there was a writing exam, phone interview, group interview, and individual interview. What I want to add is they seemed uninterested (or, rather, less interested) in credentials and much more interested in critical thinking. Your interviewers will ask a number of situational questions that provoke you to really think about your behavior at work--not so much what you've done but how you did it, from what I understood. Also, don't rely on Glassdoor's questions TOO much. Most of the questions they asked me were ones I hadn't seen in my research. As hackneyed as it might sound, if you understand yourself and your work experience/ethic deeply enough to speak comfortably about it, you will likely do great!