The first call was with an HR with no technical knowledge. I was given multiple choice questionnaire with a set of tricky domain-specific questions, which I had to solve during the video call. The second stage was a video conference which lasted 2 hours with two different interviewers. The first interview was a programming challenge with the usual algorithmic trivia. You are required to use Swift and can't use any other programming language. The interviewer appeared to be disengaged from the process and merely checked if your solution is correct and that you answered correctly algorithmic complexity questions. He specifically nitpicked typos in my code, as well as syntax errors. The second interview was for domain knowledge (iOS), and the interviewer asked me in-depth questions about iOS frameworks, Swift and Objective-C. At the end of the interview, I was given a live coding challenge to implement a timer in Swift. Overall it appears that the interviewers were looking for experienced coders with a lot of iOS domain know-how.

There were two 1-1 interviews where the interviewer (your potential future co-workers) would probe your algorithm solving skill and system design skill. And then there would be an engineering manager who probes your skills deeper with real coding for architecture design. The HR gets me updates for all the 1-1 call interviews, for example in three days. In the end, they put me in the offer process and asked me to submit five references. After two weeks later, I got the rejection for the reference check report reflected low potential. I reached out to all my referrals, and they all are surprised by the result where they gave me mostly the high ratings. I was trying to get more details, but HR can't help due to the NDA.