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

Intermediate
Apr 2026

Summary

Amazon SWE interview with a product design question about building a performance tracking app for cyclists. Pretty open-ended, which I wasn't fully prepared for.

Questions Asked (1)

Q1

Design a performance tracking application for cyclists.

System DesignProduct Sense & IdeationProduct Analytics & Metrics
Author's notes

I jumped straight into data models and GPS tracking without stopping to clarify who the users actually are.

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AI HintsAI Generated

Suggested Approach

Start by clarifying functional and non-functional requirements, then estimate scale (users, rides, data volume) to drive design decisions. Propose a high-level architecture covering data ingestion, storage, processing, and serving, and dive into critical components like real-time metrics and scalability. Discuss trade-offs and how you would measure success with product metrics.

Pro tip: At Amazon, always tie technical decisions back to customer impact and business metrics—show how your design improves the cyclist experience and supports Amazon's flywheel. Also, proactively discuss operational excellence (monitoring, deployment, cost) to demonstrate ownership.

1. Clarify Requirements

Ask questions to understand the product scope: what metrics to track (speed, distance, heart rate, power), target users (casual vs. competitive), and key features (real-time tracking, social, training plans). Define non-functional requirements like scalability, latency, and availability.

2. Estimate Scale and Data

Estimate the number of users, rides per day, data points per ride, and storage/throughput needs. This informs technology choices and highlights bottlenecks.

3. High-Level Architecture

Outline the end-to-end system: mobile app for data collection, ingestion pipeline (e.g., Kinesis), storage (e.g., S3 for raw, DynamoDB for metadata, time-series DB for metrics), processing (Lambda, Flink), and APIs for serving data to clients.

4. Deep Dive into Key Components

Pick 1-2 critical areas to detail, such as real-time metric computation, handling late/out-of-order data, or designing the data model for efficient queries. Discuss trade-offs (e.g., Lambda vs. EC2, SQL vs. NoSQL).

5. Metrics, Monitoring, and Evolution

Define product metrics (DAU, ride completion rate, user engagement) and system metrics (latency, error rates). Explain how to monitor, alert, and iterate on the design based on feedback and scale.

Key Points to Mention

  • Data ingestion from mobile devices with intermittent connectivity (offline sync, batching)
  • Choice of time-series database (e.g., Timestream) for efficient storage and querying of ride metrics
  • Real-time processing for live tracking and post-ride analytics (e.g., Kinesis + Lambda or Flink)
  • Scalability and partitioning strategies to handle millions of concurrent rides
  • Data privacy and security (encryption, access control) for user health data
  • Product metrics like user retention, average ride duration, and social sharing rate to measure success

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