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

SeniorPrefer not to say
Jun 2026

Summary

System design round at Amazon for a software engineering role. The whole session was basically one big problem about pickup point recommendations in a ride-hailing context, with a bunch of follow-ups layered on top. Felt more open-ended than I expected.

Questions Asked (5)

Q1

Design an algorithm and high-level system for recommending a pickup point in a ride-hailing app, where the passenger's location may be imprecise and the driver needs a safe, legal place to stop.

System DesignAlgorithms & Data StructuresTechnical Trade-offs
Author's notes

This one took me a minute to even scope properly.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints, then propose a two-stage solution: first, snap the imprecise passenger location to a road network and generate candidate pickup points; second, rank candidates using a multi-objective scoring function that balances safety, legality, proximity, and driver convenience. Discuss trade-offs, scalability, and how to handle real-world data imperfections.

Pro tip: Emphasize that the problem is not just about finding the closest point but about optimizing for safety and legality, which often requires incorporating external data sources like traffic regulations and historical incident reports. Also, mention the importance of A/B testing and feedback loops to continuously improve the algorithm.

1. Clarify Requirements and Constraints

Ask questions to understand the scope: What is the precision of the passenger's location? What data sources are available (e.g., road network, traffic laws, safety reports)? What are the priorities (safety vs. wait time)?

2. Design the Algorithm

Outline a two-phase approach: (1) Candidate generation by snapping the passenger location to the road network and identifying nearby legal stopping points; (2) Candidate ranking using a weighted scoring function that considers distance, safety, legality, and driver convenience.

3. Define the System Architecture

Describe high-level components: a geospatial database for road network and regulations, a service to compute candidate points, a ranking service, and integration with the ride-hailing app's dispatch system. Consider scalability and latency.

4. Address Data and Edge Cases

Discuss how to handle imprecise location (e.g., using probabilistic methods), outdated regulations, and dynamic factors like temporary no-stopping zones. Mention fallback strategies when no safe point is found.

5. Evaluate and Iterate

Propose metrics (e.g., pickup success rate, driver satisfaction, safety incidents) and a feedback loop to improve the algorithm over time. Mention A/B testing and monitoring.

Key Points to Mention

  • Use of geospatial indexing (e.g., R-trees) for efficient nearest-neighbor searches on road networks.
  • Multi-objective optimization: balancing safety, legality, proximity, and driver convenience with weighted scoring.
  • Incorporating external data: traffic regulations, historical safety data, and real-time traffic conditions.
  • Handling imprecise location: probabilistic snapping to road segments and considering uncertainty in ranking.
  • Scalability: distributed processing, caching, and precomputation of legal stopping points.
  • Trade-offs: latency vs. accuracy, and how to handle cases where no ideal pickup point exists.

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

Q2

How would you handle pickup point recommendations in constrained environments like airports or shopping malls?

System DesignProduct Sense & Ideation
Author's notes

Airports have designated zones and a totally different graph structure than a regular street.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the constraints and goals of the pickup point recommendation system, then propose a scalable architecture that balances real-time data, user context, and business rules. Emphasize how you would handle trade-offs like latency, accuracy, and dynamic environmental factors, and tie your solution back to Amazon's customer obsession and operational excellence.

Pro tip: Show awareness of the physical world's unpredictability by discussing fallback strategies and graceful degradation when data is stale or sensors fail. Also, mention how you'd measure success beyond click-through, such as pickup completion time or customer effort score.

1. Clarify Requirements and Constraints

Ask questions to understand the environment (airport vs. mall), user device (mobile app), data sources (Wi-Fi, beacons, historical data), and business goals (minimize walking, reduce congestion).

2. Define the Recommendation Problem

Frame it as a ranking problem: given a user's location, destination, time, and context, rank pickup points by suitability. Consider factors like distance, wait time, accessibility, and safety.

3. Design the System Architecture

Propose a layered architecture: data ingestion (real-time and batch), feature store, ranking model (e.g., learning-to-rank), and API for serving recommendations. Discuss scalability and low-latency requirements.

4. Address Dynamic and Uncertain Conditions

Explain how to handle changing conditions (crowds, closures) with real-time updates, fallback to static rules, and possibly reinforcement learning for adaptation.

5. Evaluate and Iterate

Define metrics (e.g., pickup time, user satisfaction, system latency) and A/B testing strategy. Discuss how to incorporate feedback loops and monitor for bias or degradation.

Key Points to Mention

  • Use of real-time data (e.g., Wi-Fi triangulation, Bluetooth beacons, computer vision) to detect crowd density and wait times.
  • Personalization based on user history, preferences, and current context (e.g., carrying luggage, time of day).
  • Trade-offs between accuracy and latency; need for low-latency serving in mobile apps.
  • Fallback mechanisms when real-time data is unavailable (e.g., static maps, historical averages).
  • Integration with existing Amazon systems like Amazon Maps, delivery stations, or locker networks.
  • Ethical considerations: privacy, accessibility, and avoiding bias in recommendations.

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

Q3

How would you use historical trip data to improve pickup point recommendations over time?

Product Analytics & MetricsSystem Design
Author's notes

Basically a learning loop question.

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AI HintsAI Generated

Suggested Approach

Start by defining the goal: improve pickup point recommendations by leveraging historical trip data to learn patterns of successful pickups. Then outline a data-driven system that ingests trip data, extracts features, trains models, and continuously updates recommendations. Finally, discuss how to measure success and iterate.

Pro tip: Emphasize the importance of defining clear success metrics (e.g., pickup success rate, time to pickup) and setting up an experimentation framework (A/B testing) to validate improvements before full rollout. This shows product sense and engineering rigor.

1. Define Objectives and Metrics

Clarify what 'improve' means: increase pickup success rate, reduce time to pickup, or enhance user satisfaction. Establish baseline metrics to measure impact.

2. Data Collection and Feature Engineering

Identify relevant historical trip data: pickup locations, timestamps, traffic, weather, user ratings, and outcomes. Engineer features like popularity, accessibility, and temporal patterns.

3. Model Development and Training

Choose models (e.g., collaborative filtering, ranking models, or reinforcement learning) to predict the best pickup points. Train on historical data, validating with time-based splits to avoid leakage.

4. Deployment and Continuous Learning

Deploy the model to serve recommendations in real-time. Implement a feedback loop to collect new trip data and periodically retrain the model to adapt to changing patterns.

5. Evaluation and Iteration

Run A/B tests to compare new recommendations against the baseline. Monitor key metrics and iterate on features, models, and business rules based on results.

Key Points to Mention

  • Use of historical data to identify patterns (e.g., time of day, location popularity, user preferences)
  • Feature engineering from trip data (e.g., distance to pickup, traffic conditions, historical success rates)
  • Choice of machine learning models (e.g., collaborative filtering, gradient boosting, or deep learning for ranking)
  • Continuous learning and feedback loops to adapt to dynamic environments
  • Evaluation metrics (e.g., pickup success rate, time to pickup, user satisfaction) and A/B testing
  • Scalability and real-time serving considerations for production systems

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

Q4

How would you adapt the system for passengers with limited mobility or who cannot walk far?

Product Sense & IdeationAdaptability & Ambiguity
Author's notes

Short answer: use accessibility constraints as a hard filter on candidate walking distance, and surface that preference in the scoring function.

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AI HintsAI Generated

Suggested Approach

Clarify the system context and the specific mobility constraints, then propose adaptations across the user journey—from discovery to post-trip—prioritizing high-impact, low-effort changes. Structure your answer around user needs, technical solutions, and trade-offs, and tie it back to Amazon's customer obsession and scalability principles.

Pro tip: Anchor your answer in a specific Amazon service (e.g., Amazon Flex, delivery routing, or a hypothetical accessible feature) and quantify impact where possible—this shows you think like an owner, not just a coder.

1. Clarify the system and constraints

Ask clarifying questions to understand which system (e.g., delivery app, warehouse robot, website) and what 'limited mobility' entails (e.g., wheelchair, elderly, temporary injury). This demonstrates you avoid assumptions and scope the problem.

2. Map the user journey and pain points

Walk through the end-to-end experience for a passenger with limited mobility, identifying friction points such as booking, navigation, waiting areas, boarding, and exiting. Prioritize the most critical barriers.

3. Propose technical adaptations

Suggest concrete changes: e.g., accessible UI (voice, large text), routing algorithms that minimize walking distance, real-time assistance features, or integration with accessibility APIs. Explain how each addresses a pain point.

4. Evaluate trade-offs and feasibility

Discuss trade-offs like cost, complexity, scalability, and impact on other users. Show how you'd prioritize quick wins vs. long-term investments, and consider Amazon's leadership principles (e.g., Customer Obsession, Invent and Simplify).

5. Define success metrics and iterate

Propose metrics (e.g., reduced walking distance, increased satisfaction scores, adoption rate) and a plan to test, learn, and iterate. Emphasize accessibility as an ongoing commitment, not a one-time fix.

Key Points to Mention

  • Accessibility standards (WCAG, ADA) and inclusive design principles
  • Personalization and user profiles to remember mobility needs
  • Real-time data and IoT (e.g., sensors, beacons) for dynamic routing
  • Voice and multimodal interfaces for hands-free interaction
  • Partnerships with accessibility organizations for user testing
  • Scalability and cost-effectiveness across Amazon's global systems

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

Q5

What metrics would you use to A/B test changes to the pickup recommendation algorithm?

A/B Testing & ExperimentationProduct Analytics & Metrics
Author's notes

I went with cancellation rate, average total trip time from request to pickup, and driver circling time as primary metrics.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the goal of the pickup recommendation algorithm—likely to increase customer engagement and conversion while minimizing operational costs. Then propose a mix of primary metrics (e.g., click-through rate, conversion rate) and guardrail metrics (e.g., delivery delays, cost per pickup) to measure both success and unintended consequences. Finally, emphasize the importance of statistical rigor, including sample size calculation and long-term holdout groups.

Pro tip: Demonstrate business acumen by linking metrics to Amazon's leadership principles, such as Customer Obsession and Frugality, and mention how you'd balance short-term wins with long-term customer trust.

1. Clarify the hypothesis and goal

Ask clarifying questions to understand what change is being tested and what the desired outcome is (e.g., increase pickup adoption, reduce delivery costs).

2. Define primary success metrics

Identify metrics that directly measure the hypothesis, such as pickup selection rate, conversion rate, or average order value for pickup orders.

3. Identify guardrail metrics

List metrics to ensure the change doesn't harm other parts of the business, like delivery time, customer satisfaction (CSAT), or operational costs.

4. Consider secondary and diagnostic metrics

Include metrics that provide insight into why the change worked or didn't, such as click-through rate on recommendations or time to pick up.

5. Plan for statistical validity and long-term impact

Discuss sample size, duration, and potential long-term holdout to measure sustained effects and avoid novelty effects.

Key Points to Mention

  • Primary metric: pickup selection rate or conversion rate
  • Guardrail metrics: delivery cost, customer satisfaction, delivery speed
  • Secondary metrics: click-through rate, time to pickup, repeat usage
  • Statistical significance and power analysis
  • Long-term holdout to measure sustained impact
  • Segment analysis (e.g., by customer tenure or location)

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