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Amazon·Software Engineer·Onsite - System Design / Architecture·Senior

Senior
Jul 2026

Summary

Amazon system design-ish round where they give you a real team problem and basically expect you to run a mini product-eng session on the spot. More open-ended than I expected for a software engineer role.

Questions Asked (1)

Q1

Given a team-specific business problem, walk through how you'd approach it end-to-end: define success metrics and constraints, generate hypotheses, figure out what data and instrumentation you need, design an MVP experiment with control and variant groups, weigh ML approaches against simpler baselines, and call out risks with mitigations.

A/B Testing & ExperimentationProduct Analytics & MetricsTechnical Trade-offs
Author's notes

This was a lot to hold in your head at once.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the business problem and aligning on a single primary success metric with guardrail metrics, then structure your answer as a logical narrative from problem definition to experiment design to risk assessment. Emphasize iterative learning and data-driven decision-making, showing how you'd validate assumptions with an MVP before investing in complex ML solutions.

Pro tip: Anchor your answer in Amazon's leadership principles: explicitly tie your approach to Customer Obsession (defining success from the customer's perspective) and Invent and Simplify (favoring simple baselines over complex ML). Also, mention how you'd use Amazon's internal experimentation tools like Weblab or CloudWatch for instrumentation.

1. Define Success and Constraints

Clarify the business problem and identify the primary success metric (e.g., conversion rate, engagement) along with guardrail metrics (e.g., latency, error rates). List constraints such as budget, timeline, and technical feasibility.

2. Generate Hypotheses and Data Needs

Brainstorm potential causes and solutions, then prioritize hypotheses based on impact and effort. Determine what data and instrumentation are required to measure the metrics, including logging, tracking, and existing data sources.

3. Design MVP Experiment

Outline a minimal viable experiment with control and variant groups, specifying randomization unit, sample size, duration, and success criteria. Ensure the experiment is statistically powered and addresses potential confounders.

4. Evaluate ML vs. Baselines

Compare simple baselines (e.g., rule-based, heuristics) against ML approaches, considering trade-offs in complexity, interpretability, and time-to-market. Recommend starting with the simplest solution that could work.

5. Identify Risks and Mitigations

Call out risks such as data leakage, novelty effects, technical debt, or ethical concerns, and propose mitigations like holdout groups, phased rollouts, or monitoring dashboards.

Key Points to Mention

  • Primary and guardrail metrics with clear definitions and targets
  • Hypothesis prioritization using frameworks like ICE (Impact, Confidence, Ease)
  • Instrumentation plan: event logging, data pipelines, and validation
  • Experiment design: randomization, control/variant, power analysis, and duration
  • Trade-offs between ML and simpler baselines (e.g., interpretability, latency, cost)
  • Risk mitigation strategies: A/A tests, novelty effect checks, and rollback plans

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.