3 interviews. 1st is 20 min with recruiter. 2nd call from an engineer somewhat technical. 3rd create web-based application calling some 3rd party rest calls. Can be created in any language, then 3hr on-site interview. Frustrating part is no feed back after the amount of time you've dedicated to the process. Simply told they liked me but decided to not extend an offer. Even calling too see what areas I could improve on. Simply told the same thing. At least have the courtesy to discuss the interview after the amount of time you expect from the interviewer.

Had to go through 4-6 rounds (based on how you differentiate a conversation from an interview) for about 2.5 months. They expect you to spend days on a take home project. The HR kept saying "they like you", "they are interested" etc., until they completely go silent and don't respond until you ask for an update. After spending weeks on their interview, I felt it was straight up unprofessional to keep an interviewee hanging.