The interview process is very similar to what everyone else has posted. I was interviewing for a position on the legal team at Palantir. I had a quick phone interview with a member of the team. It was a very general interview and I believe they were simply screening me to make sure I had the right skills. I was asked how I heard about the company, etc. The next day I received an e-mail asking me to come in to their Palo Alto office for an in-person interview with members of the team.
The office setting is very casual. Palo Alto is very warm so people are walking around in shorts, t-shirts and flip flops. Everyone at the office was very nice and helpful. It seems like the company is in the middle of a major hiring boom as there were several people waiting to be interviewed for various teams. I interviewed with two people on the team. Both individuals were again very nice and asked more questions about personality than skills. After two interviews, I was led into a room with the other candidates where you are shown a video about either current or past projects that the company is involved in. They also give you a brief demo on their main products and how they're used. I finished off the day with one last interview and then was done for the day.
Unfortunately, I did not get a job offer from the company. Like many others, I felt that I interviewed well and actually thought I would be moving forward with the company. I thought I had made a genuine connection with each of my interviewers. However, I received a call from my recruiter indicating otherwise. They explained to my recruiter that during the my initial phone interview I did not ask any questions about the company (although I do recall asking several) and therefore was not excited about the company. Apparently, that was not offensive enough so I was granted an in-person interview. During my in-person interview, the interviewer explained that she would be coming in that weekend to get some work done. Using that as a perfect segue, I asked her if she worked a lot of overtime and if telecommuting was a possibility in the position I was interviewing for. This also raised a red flag for some of the people I interviewed with. For a job that requires overtime and weekend work, I don't believe asking about the amount of time actually spent on overtime and weekends is necessarily a negative. I thought I approached the question professionally.
Overall, the interview experience was definitely very casual. Everyone was very helpful and nice. They are definitely very selective about their candidates as you can see by the reasons that were used to decline my application. It definitely seems like a great company that is growing very fast.