30 minute HR call, followed by 30 minute hiring manager call (general CV overview), followed by 4 45 minute interviews with various engineers. One behavioural, the rest mostly technical, including programming tasks. Difficulty wasn't too bad for the most part. One quite difficult programming task, but it's all relative. They provided information on what each interview would roughly cover which was very helpful to prepare, but sometimes wasn't fully accurate. All interviews quite relaxed and friendly, they spend time explaining the role and company, I think overall the process is a bit long- I don't think they really need 6 calls to determine if you are a good fit. 4 hours of actual interviewing, but plenty of time you spend around that preparing, it's a big time commitment, so not sure I would apply again.