Unlike other interviews, I felt like I could really prepare for this one. Although, you don't know the details of the REST API you'll need to implement, you can get really far by preparing ahead of time. I went through the process multiple times ahead of time, so when the interview came I was ready to crunch through in the 90 minutes I had. Don't expect to complete everything in 90 minutes, so be choosey about where to focus your time. (Don't get bogged down in one thing if it would be better to move onto something else.) While the interview was overall positive, there were a couple of instances in which the interviewers didn't seem to be on the same page as the interview material I was sent. The first person who was supposed to be prepared to give me the REST interface assignment assumed I already had been given one. Also, I was told to prepare a Powerpoint but my interviewers failed to ask about that (but I presented it anyway).