Citadel Software Engineer Behavioral Interview (Chicago) — Ownership, Impact, and High‑stakes Decision‑Making

This behavioral interview assesses how a software engineer performs in Citadel’s fast, data‑driven, and high‑accountability environment supporting mission‑critical trading and research systems. Expect a resume deep‑dive with quantified outcomes (e.g., P99 latency, throughput, incident MTTR), layered follow‑ups that probe first‑principles reasoning and trade‑offs, and scenario questions centered on production ownership during market hours (incident response, risk mitigation, rollbacks, and communication). Interviewers typically explore: end‑to‑end ownership of services and tooling; decision‑making under time pressure and incomplete information; collaboration with quantitative researchers, traders, and infrastructure/SRE partners; prioritization and delivery against shifting signals; quality and reliability mindset (runbooks, post‑mortems, preventing repeat failures); and integrity, compliance, and confidentiality expectations common to a leading hedge fund. Communication is expected to be concise and structured (STAR), with clear metrics, alternatives considered, and lessons learned. The style is rigorous and iterative—anticipate detailed ‘why/what changed/what would you do differently’ probing and evidence of raising the bar through mentorship, code reviews, and continuous improvement. Typical format: 60 minutes with an engineer or manager, including time for your questions.