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intermediate Phase · API Design Interview

Status Codes

Select appropriate status codes for all scenarios.

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Status Codes

Mapping

Operation Status
Successful GET 200 OK
Successful POST 201 Created
Successful DELETE 204 No Content
Invalid input 400/422
Not found 404
Unauthorized 401
Forbidden 403

Key Points

  • Understanding API Design: Status Codes is essential for production systems
  • Always consider scalability and maintainability
  • Test thoroughly before deploying to production
  • Monitor performance and set up alerting

Common Patterns

  1. Validation: Always validate input at the boundary
  2. Error Handling: Use structured error responses
  3. Logging: Log key events for debugging
  4. Testing: Unit, integration, and load tests
  5. Documentation: Keep docs updated with code changes

API Best Practices

Design Principles

  • Use nouns, not verbs
  • Plural resource names
  • Consistent naming conventions
  • Proper HTTP status codes

Versioning

  • URI versioning (/v1/resource)
  • Header versioning
  • Deprecation policy

Documentation

  • OpenAPI/Swagger specs
  • Request/Response examples
  • Error code documentation
  • Rate limit documentation

Key Points

  • Understanding API Design: Status Codes is essential for production systems
  • Always consider scalability and maintainability
  • Test thoroughly before deploying to production
  • Monitor performance and set up alerting

Common Patterns

  1. Validation: Always validate input at the boundary
  2. Error Handling: Use structured error responses
  3. Logging: Log key events for debugging
  4. Testing: Unit, integration, and load tests
  5. Documentation: Keep docs updated with code changes

Practice Problems

0 / 3 solved
Implement API Design: Status Codes

Design and implement a solution for API Design: Status Codes in a backend system. Consider scalability, error handling, and production readiness.

Solution 
// API Design: Status Codes implementation
// Key aspects: validation, error handling, logging, testing

public class APIDesignStatusCodes {
    // Production-ready implementation
}
API Design: Status Codes Edge Cases

Identify and handle edge cases for API Design: Status Codes. What happens under high load, with invalid input, or during failures?

Solution 
// Edge case handling:
// 1. Null/empty input -> validation
// 2. High load -> rate limiting, queuing
// 3. Failures -> retries, circuit breaker
// 4. Concurrent access -> locks, idempotency
API Design: Status Codes Testing Strategy

Write a testing strategy for API Design: Status Codes. Include unit tests, integration tests, and performance tests.

Solution 
// Test plan:
// - Unit: 80% coverage target
// - Integration: API contracts
// - Performance: latency, throughput
// - Chaos: failure injection

Quiz

1. POST create returns?

Question 1 options

2. DELETE success returns?

Question 2 options

3. What is a common mistake when implementing API Design: Status Codes?

Question 3 options

Flashcards

Question

POST create status?

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Answer

201 Created

Question

DELETE success status?

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Answer

204 No Content

Question

API Design: Status Codes best practices

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Answer

Follow SOLID principles, write clean code, test thoroughly, document decisions, and monitor in production.

Revision Notes

Key Takeaways

  • 1. 200: OK, 201: Created, 204: No Content
  • 2. 400/422: validation, 404: not found
  • 3. 401: unauthorized, 403: forbidden
  • 4. Map each operation to correct status

Interview Tips

  • • Choose correct status codes
  • • Map operations to statuses

Cheat Sheet

Status Codes

  • 200: OK, 201: Created, 204: No Content
  • 400/422: validation
  • 404: not found
  • 401: unauthorized, 403: forbidden