Choose one impactful project from your resume and deep-dive it in 8–10 minutes: define the problem and business goal, baseline and target, your precise role and headcount, the key design decisions and rejected alternatives, the riskiest assumptions and how you retired them, the metrics and how you measured causally, what failed and how you recovered, how you handled security/privacy constraints, and quantified outcomes. Prepare to answer two probing follow-ups (one on scalability limits, one on metric validity) with concrete numbers and dates.