I applied online and got a response for a phone interview with one of the engineers. After that, I was invited on-site and spoke with 5 people: 2 PMs, 3 engineers. It was a very relaxed and casual interview. Discussed 3D math, C++ trivia, and culture fit questions. Everyone was very nice and up-front and pleasant to be talking to. Office is very cool for the space that's there (startup environment). Had a good time during the interview.