I was referred to Citadel via a third-party recruiter. I interviewed for the NXT program (recruitment program for engineers with 1-6 work experience). There were two rounds of interviews, both virtual due to COVID-19. I had the first round in late June and the second round in early August. The first round was a 1h Zoom interview conducted by a junior engineer. It consisted of a background screen plus a live coding problem. The interviewer patient and asking thoughtful follow-up probing questions from my resume. The second round was a 5h Zoom interview session, with 30mins break in between for lunch. I had back-to-back 1-1 interviews with engineers and engineering managers of various levels of seniority. They did ask some tough technical questions. Behavioral questions were OK. Overall I was very impressed with the people I interviewed with ("no duds" as one of the interviewers put it). Citadel has a high quality bar. I didn't get the offer but if you did, you can be sure to be working alongside very talented people.