The interview process started with a 4 hour long (1 problem) code challenge that was an interesting and real life style algorithm problem. I thought it was well thought out and would accurately capture problem solving skills.
The second round was a 1:1 video interview code challenge that focused on data structures and time efficiency. The interviewer was extremely stiff and difficult to understand.
The final stage round was a panel of 4 back to back interviews, ranging from 30-60 minutes. All were a combination of behavioral and technical. Two interviewers were great - candid about their experience, easy to talk to and encouraging as I went through the challenges.
Another was hard to read but pleasant. The last was extremely rude, literally saying things like, "I can't grade you based on your inner monologue," and just saying, "No," instead of trying to provide some guidance.
Based on the variety of interviewers, I'm unsure if the company culture is great. Two people seemed awful to work with and two seemed great to work with. Heavy emphasis on OOP and time complexity analysis throughout.
Was told at the end that they interviewed roughly 1,600+ candidates for 4-6 openings.