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Amazon·Software Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say
Apr 2026

Summary

Amazon SWE interview with a system design coding task focused on building a camera data interface. The problem sounded straightforward but the flexibility and extensibility requirements made it more interesting than I expected.

Questions Asked (1)

Q1

Design and implement a camera data interface in Python with recv_data and send_data functions. The design should be flexible, extensible, and backed by sufficient test cases.

API & IntegrationsSystem DesignTechnical Trade-offs
Author's notes

My first instinct was to just write two functions and call it done, which would've been a mistake.

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AI HintsAI Generated

Suggested Approach

Start by clarifying requirements and constraints, then propose a flexible interface using abstract base classes or protocols, and discuss implementation details for recv_data and send_data. Emphasize extensibility and testability, and outline a comprehensive test strategy covering unit, integration, and edge cases.

Pro tip: Demonstrate Amazon's Leadership Principles by proactively discussing trade-offs (e.g., simplicity vs. flexibility) and how your design scales, and mention writing tests first to drive the interface design.

1. Clarify Requirements and Constraints

Ask questions to understand data types, performance needs, error handling, and integration points. This ensures the design meets actual needs and shows you think before coding.

2. Design the Interface

Define an abstract base class or protocol with recv_data and send_data methods, specifying parameters and return types. Consider using generics or type hints for flexibility.

3. Implement a Concrete Class

Provide a sample implementation (e.g., for a specific camera) that adheres to the interface, handling edge cases like timeouts and partial data. Discuss how to extend for other cameras.

4. Outline Test Strategy

Describe unit tests for the interface and implementation, using mocks for dependencies. Cover normal operation, error conditions, and performance aspects.

5. Discuss Trade-offs and Extensibility

Explain design decisions, such as why you chose an abstract class over a simple function, and how the design supports future changes (e.g., new camera types).

Key Points to Mention

  • Use of abstract base classes (ABCs) or protocols for interface definition
  • Type hints and generics for flexibility and type safety
  • Error handling and retry mechanisms for robustness
  • Test-driven development (TDD) and mocking for unit tests
  • Separation of concerns and dependency injection for testability
  • Scalability and performance considerations (e.g., async I/O, buffering)

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