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Walmart Labs·Software Engineer·Onsite - System Design / Architecture·Senior

SeniorPrefer not to say
Jun 2026

Summary

System design round at Walmart Labs for a software engineer role. The question was a beast, basically a full product and architecture deep dive into airplane seatback entertainment systems. Walked out not totally sure how I did.

Questions Asked (1)

Q1

Design an in-seat personal entertainment system for commercial aircraft. Cover the full UI and interaction flows, client architecture, offline caching, communication with cabin and ground services, DRM, fault tolerance, accessibility, parental controls, A/B experimentation, and telemetry.

System DesignTechnical Trade-offsA/B Testing & Experimentation
Author's notes

This thing sprawls in every direction and I made the mistake of trying to cover everything at the same depth.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints (e.g., scale, connectivity, hardware) and then walk through the system from a high-level architecture down to key components. Focus on trade-offs, especially around offline-first design, fault tolerance, and how you would validate features through A/B testing and telemetry. Tie back to Walmart Labs' emphasis on experimentation and reliability.

Pro tip: Emphasize the offline-first nature of the system and how you handle synchronization and conflict resolution when connectivity is intermittent. Also, highlight how you would design for testability and gradual rollout of features using feature flags and A/B testing to minimize risk.

1. Clarify Requirements and Constraints

Ask questions to understand scale (number of seats, flights per day), connectivity (satellite, air-to-ground), hardware (seat-back screens, tablets), and regulatory constraints (DRM, accessibility). Define functional and non-functional requirements.

2. High-Level Architecture

Outline the client-server architecture: seat client, cabin server, ground services. Describe data flow for content delivery, user interactions, and telemetry. Mention offline caching strategy and synchronization.

3. Deep Dive into Key Components

Detail UI/UX flows, client architecture (e.g., native vs. web), DRM implementation, fault tolerance (redundancy, graceful degradation), accessibility (WCAG), parental controls, and A/B experimentation framework.

4. Address Trade-offs and Scalability

Discuss trade-offs: e.g., caching vs. storage, real-time vs. batch telemetry, DRM robustness vs. performance. Explain how the system scales with number of aircraft and users.

5. Summarize and Validate

Summarize the design, highlighting how it meets requirements. Mention how you would validate through A/B tests, telemetry, and fault injection. Be open to feedback and iterate.

Key Points to Mention

  • Offline-first design with local caching and synchronization when connectivity is available.
  • DRM for content protection, including key management and secure playback.
  • Fault tolerance: redundancy, graceful degradation, and recovery mechanisms.
  • Accessibility: compliance with WCAG, features like closed captions, audio descriptions, and screen reader support.
  • Parental controls: PIN protection, content filtering, and time limits.
  • A/B experimentation and telemetry: feature flags, metrics collection, and analysis for continuous improvement.

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