Started with a phone interview, ~30 minutes. I reached out to the HR representative who posted this job after about a week and a half of waiting. I think it worked in my favor because I heard back shortly after. Another week or two later I was invited to the headquarters in Centennial, CO. The onsite interview lasted three hours, and was not overly formal but did involve some assessment and detailed discussion about how I would handle the job responsibilities. I enjoyed the chance to see the office (very cool space) and meet some FASTies (who were all incredibly outgoing and welcoming). They covered the cost of getting me there, too. I chose "difficult" to describe the interview only because I don't think a successful applicant could easily coast through it. If you are present, engaged, and well-prepared, you have a good shot, but that entails your mental A-game and no slouching. Overall a very positive and fair interview experience that made me more excited to work for the company!