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

SeniorPrefer not to say

Apr 2026

Summary

Microsoft interview with a single open-ended system design question about building a hotel security system. Not much context given about the role but it felt like a senior-level design round. Pretty broad prompt with a lot of room to go wrong.

Questions Asked (1)

Design a security system for a hotel that could be located anywhere in the world.

System DesignAdaptability & AmbiguityTechnical Trade-offs

Author's notes

The 'anywhere in the world' part threw me a bit.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the ambiguous requirements—what 'security system' means (physical, cyber, or both), the scale of the hotel, and the 'anywhere in the world' constraint. Then propose a modular, cloud-based architecture that can adapt to local regulations and infrastructure, and discuss trade-offs between cost, latency, and reliability.

Pro tip: Acknowledge that 'anywhere in the world' implies diverse legal and infrastructural environments; show maturity by suggesting a core system with region-specific adapters and emphasizing data sovereignty and compliance.

1. Clarify Requirements and Scope

Ask questions to understand what the security system should cover (e.g., access control, surveillance, emergency response) and the expected scale (number of rooms, locations).

2. Define High-Level Architecture

Outline a cloud-based, modular system with components like sensors, central management, and user interfaces, ensuring it can be deployed globally.

3. Address Global Variability

Discuss how to handle differences in regulations (e.g., GDPR, local privacy laws), infrastructure (e.g., internet reliability), and cultural factors.

4. Discuss Trade-offs and Technologies

Compare options for data storage (cloud vs. edge), communication protocols, and redundancy to balance cost, latency, and reliability.

5. Summarize and Conclude

Recap the proposed design, emphasizing scalability, compliance, and adaptability, and invite further questions.

Key Points to Mention

Modular architecture with region-specific adapters for compliance and infrastructure
Data sovereignty and privacy regulations (e.g., GDPR, CCPA) and how to handle data localization
Use of cloud services (e.g., Azure) with edge computing for low-latency processing
Scalability and reliability through redundancy and failover mechanisms
Integration with existing hotel systems (e.g., booking, IoT devices)
Security of the security system itself (encryption, access controls, regular audits)

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