I did a phone interview and then came in for in person interviews and a pair programming exercise. During the exercise I worked with the CEO on building an app from scratch. I decided to do it in Swift (this was back in 2015 so Swift was new) and I had never professionally done Swift development so I made a lot of mistakes. The CEO really impressed me with his knowledge of iOS development, turns out he literally wrote the book on it. I also had a group meeting with basically the whole company and it was a little intimidating but everyone was very nice.