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

Senior
Jun 2026

Summary

Google data engineer interview with a system design prompt about building a high-tech gym. One question, open-ended, and the kind of thing that sounds breezy until you're actually sitting there trying to figure out what 'high-tech' even means in this context.

Questions Asked (1)

Q1

How would you design a high-tech gym? Walk through the systems and data infrastructure you'd build.

System DesignData ModelingTechnical Trade-offs
Author's notes

Spent the first two minutes just trying to scope it.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the scope and requirements of the high-tech gym, then propose a high-level architecture covering key systems like member management, equipment IoT, and data analytics. Dive into data infrastructure, discussing data ingestion, storage, processing, and serving layers, and highlight trade-offs in scalability, latency, and cost.

Pro tip: Emphasize how you would leverage Google Cloud services (e.g., Pub/Sub, BigQuery, Dataflow) to build a scalable and reliable solution, showing alignment with the company's ecosystem. Also, discuss how you would measure success and iterate based on user feedback and data.

1. Clarify Requirements

Ask questions to understand the gym's scale, user base, key features (e.g., personalized workouts, equipment tracking), and non-functional requirements like latency, availability, and budget.

2. High-Level Architecture

Outline the main components: member-facing apps, IoT sensors on equipment, backend services, and data pipelines. Sketch how they interact and the data flow.

3. Data Infrastructure Design

Detail the data ingestion (e.g., streaming from sensors), storage (e.g., data lake, time-series DB), processing (batch and stream), and serving layers (APIs, dashboards). Discuss technologies and trade-offs.

4. Scalability and Reliability

Explain how the system scales with more gyms and users, ensuring fault tolerance and low latency. Mention partitioning, replication, and monitoring.

5. Trade-offs and Future Work

Summarize key trade-offs (e.g., cost vs. performance, consistency vs. availability) and suggest potential enhancements like ML for personalized recommendations.

Key Points to Mention

  • Use of IoT sensors and real-time data streaming for equipment usage and user biometrics.
  • Data storage options: time-series databases for sensor data, relational DB for user profiles, and a data lake for analytics.
  • Stream and batch processing with tools like Apache Beam/Dataflow for real-time insights and historical analysis.
  • API design for member apps and third-party integrations, ensuring security and privacy (e.g., OAuth, encryption).
  • Scalability via horizontal scaling, load balancing, and managed services (e.g., Google Kubernetes Engine).
  • Trade-offs: consistency vs. availability (CAP theorem), cost of real-time vs. batch, and build vs. buy decisions.

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