Overall, Square's interview process was fairly standard. They try to improve upon the process, and in some ways they do, but it ultimately falls short of their goals. For the most part, it comes down to luck (who you get to interview you) and memorization. With 3 coding interviews, 2 technical discussions, and a talk with the manager, this is a test of endurance.

Process: The interview process is described as "pair programming." The issue is that they leave it up to the interviewer to determine how to implement this. Out of the four programming exercises I had, only one felt like true pair programming. The others mostly involved the interviewer taking notes and being only semi-engaged (or slightly bored?). So, expect more of a whiteboard session with an IDE and Google. After the coding, you'll have open-ended discussions with people from various teams. This isn't inherently tough, but after 3 hours of coding with 3 separate people, it can be difficult to remain engaged.

Questions: Despite what I read elsewhere, most of my questions were variants of standard interview questions: "Design this," "manipulate that," "find this," etc. Nothing was too difficult, but these aren't tasks you perform in the real world, nor are they things you can solve and implement while still entertaining the interviewer within the hour given. Therefore, memorize basic implementations of standard problems so you can dedicate your mental energy to engaging the interviewer during your coding presentation.

I would say my experience was fairly negative, but I'll give props for a slightly better interview experience than what I've had at other companies. I didn't receive confirmation of my onsite until the night before (though I had been in contact with the recruiter, so I knew things were still on). Of the four coding interviewers I worked with, one was fantastic, two were fine (they took notes but offered little feedback or engagement), and one was probably among my top worst interviewers. The interview is a full day, which is pretty exhausting and works against most candidates. It also makes the process difficult for people who currently have jobs.

Not going into detail, but they were variations of standard OOP, String, and mathematical questions.