Candidates report a Citadel software engineer loop weighted toward the early stages: of 48 reported questions, 23 come from technical screens and 11 from online assessments, with 10 from onsites and 4 from HR screens. Coding and algorithms dominates the mix at 31 questions, ahead of system design at 7, behavioral and leadership at 5 and software engineering fundamentals at 2, with single reports in ML system design and machine learning. Difficulty clusters in the middle, at 36 medium against 8 hard and 4 easy. The reported problems lean on classic algorithmic patterns with a systems edge, including returning a valid dependency order for named tasks, performing an external merge sort with a heap, minimizing changes to make every password block palindromic, and maximizing earnings by converting days off. The last two each appear in an online assessment report and again in an HR screen report. Concurrency shows up directly, with a thread-safe shared counter and a single-producer multi-consumer ring buffer, both from technical screens. System design questions cover a low-latency metrics and alerting platform and inventory availability with order placement. 7 first-hand interview experiences cover the loop, including a screen run entirely on a whiteboard with a quant developer and no code editor, and a HackerRank online assessment with two coding problems in 75 minutes.