It was an incredibly long process--almost 2 months from when I first put in my application until my onsite interview. Partly this was because Palantir kept cancelling/rescheduling the interviews at the last minute, which was very frustrating. An acquaintance had forwarded my application; then I spoke to a recruiter on the phone, who barely asked me any questions. I had a phone interview several weeks later, where I was asked to talk more about my background and interest in the job and I also got relatively standard behavioral questions (e.g., how do you solve problems?). Several weeks afterwards I had an onsite interview. It was about 3hrs and I met with 4 different people, mostly deployment strategists, but also one engineer, and one more senior person. It was a mixture of behavioral questions and problem-solving questions (including the Kayak one that other people on this site have mentioned). A week later the recruiter e-mailed to let me know that they weren't going to move forward with my application.