First was with a lead engineer (technical), then with a recruiter (behavioral), then with another lead engineer (technical), future would have been on site. It was a very accelerated timeline and fast process.

Multiple rounds of interviews ending with an all day onsite interview. Asked questions about background, classic textbook problems, and coworker interactions. Very technical and difficult. Lots of time spent trying to understand your thought process

Rigorous but fairly reasonable in my experience. The technical problems often has a twist but if you have strong fundamentals you should be able to perform well. The recruiter and interviewers I interacted with are all very nice people.