Applied through an employee referral, exchanged a few e-mails with a recruiter and then organised a phone interview. First phone interview consisted of some conversation about what I was doing at the moment, and then algorithms questions. Received a second phone interview which was similar, some casual discussion about different languages and why I liked them, then some coding/algorithms questions. Was supposed to go for on-site interviews in London, but both team members had last minute emergencies to sort out, so these work reorganised to skype interviews, similar questions to the other phone interviews, but in a more conversational style. Flown out to interviews in California, put up in a very nice hotel for a few night with everything paid for, despite only being interviewed on 1 day. Interviews all day with different team members with a presentation of the product in the middle, and was taken to lunch by one team member. After lunch a quick chat with my recruiter making sure we had everything sorted and filling me in on some bits of the job that hadn't been covered yet, then 2 interviews with the founders.