API Design Interview Questions

API Design Interview Questions

API design questions test your ability to create clean, scalable, and secure interfaces between services and clients.

Expect discussions on REST vs GraphQL, pagination strategies, rate limiting, versioning, and authentication patterns.

Interviewers want to see practical design sense, not just theoretical knowledge of HTTP methods.

1540Questions
250Companies
Easy 78 • Medium 899 • Hard 563Difficulty mix

Common API design interview patterns

  • REST resource modeling and URL structure
  • GraphQL vs REST trade-offs
  • Cursor-based vs offset pagination
  • Rate limiting and throttling strategies
  • API versioning approaches
  • Idempotency for safe retries
  • Authentication and authorization patterns (OAuth, JWT, API keys)

API design interview questions

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Common mistakes with API design

  • Overusing POST for operations that should be GET
  • Not designing for backward compatibility
  • Exposing internal implementation details in the API surface
  • Ignoring error response formats and status codes
  • Not considering rate limiting from the start

How API design questions are evaluated

Design for the consumer, not the implementation.

Show awareness of backward compatibility and versioning from day one.

Discuss security considerations naturally as part of the design.

Related system design concepts