Hackerrank challenge was the first step of the interview process. First call was a phone call with recruiter who was very helpful in laying out the rest of the interview process. Next step was a 60 minute technical interview with a software engineer focused on solving and optimizing the solution for one question. Next was the virtual "in-office" interviews with two developers, one more senior and one a more recent hire. Both provided challenging questions but followed a back-and-forth approach to interviewing that felt cooperative and less stressful.