First, I was asked to do a phone screen with an engineer. It went reasonably well. He asked me some questions about my resume, and about more general programming knowledge, topics like interfaces, OOP (think four pillars), and dependency injection. After the phone screen, I was offered an on campus interview. I had one session with the head of engineering, then a 2 on 1 session with two engineers. They send everyone a coding challenge, so make sure that you understand the app that you build, because you will do a full code review and be expected to discuss every design decision you made. My best advice is to get to know interfaces inside and out (when to use them, why they're useful, how to use them). Also, there were lots of questions on dependency injection!