Interview Prep — Senior ML Engineer

The four loops a senior MLE candidacy runs through, mapped to this track:

LoopWhat's testedPrep docTrack foundation
ML system designend-to-end architecture judgment01Phases 02–09, 13; system-design/
ML fundamentals + codingdo you actually know how it works02Phases 04–07, 11 labs
MLOps / platform depthproduction lifecycle ownership03Phases 01–03, 08–09, 12
GenAI production judgmentbeyond-the-demo LLM engineering04Phase 10 + LLM track
Behavioral (senior bar)judgment, ambiguity, leadership05your capstone + work history

How to use these

  • Every answer here is written at the bar the JD sets (7–9+ years): structure first, numbers where they bite, tradeoffs named, limits admitted. Don't memorize prose — internalize the skeletons and regenerate in your own words.
  • The coding-adjacent questions are literally the track's labs ("implement NDCG", "build an SRM check", "point-in-time join") — if you built the labs, rehearse by re-deriving, not re-reading.
  • For system design, rehearse the 2-minute capstone tour (Phase 13 WARMUP Ch. 5) — interviewers steer; you need entry points, not scripts.

The senior-bar rubric (what interviewers actually grade)

  1. Clarify before designing — requirements, scale, constraints, the metric.
  2. Baseline first — the candidate who says "popularity / seasonal-naive / logistic regression first, here's why" outranks the one who opens with a transformer.
  3. Name the seams — training-serving skew, leakage, feedback loops, label delay. Senior candidates volunteer the failure modes; juniors wait to be asked.
  4. Quantify — KV-cache math, sample sizes, latency budgets, cost per 1k requests. Two or three well-chosen numbers per hour signal depth.
  5. Decide — end ambiguous tradeoffs with a recommendation and its trigger for revisiting, not a survey.