System Design Walkthroughs — Senior ML Engineer
Five full-depth designs at the altitude a senior loop expects. Each follows the method from interview-prep/01 — requirements → metrics & baseline → data/features → models → serving → evaluation & rollout → operations → failure modes & evolution — and each maps to the track phases (and a Phase 13 capstone) where you built the components.
| Walkthrough | The interview question it answers | Built in |
|---|---|---|
| 01 — Feature Store & ML Data Platform | "Design the data layer for ML at a company with 30 teams" | P01–03, 08; capstone 02 |
| 02 — Recommendation System End-to-End | "Design product recommendations for an e-commerce site" | P03–06, 09, 11; capstone 01 |
| 03 — GenAI Assistant Platform | "Design an enterprise RAG assistant with safety controls" | P04, 09–12; capstone 03 |
| 04 — Online Experimentation Platform | "Design the A/B testing system itself" | P09, 11; every capstone's readout |
| 05 — Forecasting Platform | "Design demand forecasting for 50k SKUs × 500 stores" | P07–09, 12; capstone 04 |
How to use these
- Read each after its phases — these are consolidations, not introductions.
- Rehearse delivery: 2-minute end-to-end tour first, then deep-dive where steered. Interviewers grade the tour's completeness and the dives' depth; candidates who only have one mode (all-overview or all-rabbit-hole) plateau.
- Every design states its numbers (budgets, scales, thresholds) — recompute them for the interviewer's stated scale rather than reciting these.
- The failure-modes section is the differentiator: volunteer them. The seven recurring seams — skew, leakage, label delay, feedback loops, cold start, experiment hygiene, drift laundering — appear across all five designs with design-specific shapes.