API Development interview questions

Review short answers, detailed answers, practical code and common mistakes.

1. How would you explain API Basics in API Development during an interview?beginner

API Basics is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem api basics solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for API Basics
{
  "route": "/api/v1/api-basics",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

2. How would you explain HTTP Protocols and Methods in API Development during an interview?beginner

HTTP Protocols and Methods is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem http protocols and methods solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

3. How would you explain REST Architecture Guidelines in API Development during an interview?beginner

REST Architecture Guidelines is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem rest architecture guidelines solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

4. How would you explain URL Path Design in API Development during an interview?beginner

URL Path Design is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem url path design solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for URL Path Design
{
  "route": "/api/v1/url-path-design",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

5. How would you explain Request Headers in API Development during an interview?beginner

Request Headers is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem request headers solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

6. How would you explain Response Status Codes in API Development during an interview?beginner

Response Status Codes is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem response status codes solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

7. How would you explain JSON Payload Format in API Development during an interview?beginner

JSON Payload Format is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem json payload format solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

{
  "id": 42,
  "total": 56,
  "status": "paid",
  "customer": "Asha",
  "items": [{ "sku": "key-01", "qty": 1 }]
}

8. How would you explain Query Parameters in API Development during an interview?beginner

Query Parameters is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem query parameters solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

9. How would you explain Pagination Patterns in API Development during an interview?beginner

Pagination Patterns is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem pagination patterns solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

10. How would you explain Filtering and Sorting APIs in API Development during an interview?beginner

Filtering and Sorting APIs is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem filtering and sorting apis solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for Filtering and Sorting APIs
{
  "route": "/api/v1/filtering-and-sorting-apis",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

11. How would you explain Authentication Options in API Development during an interview?intermediate

Authentication Options is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem authentication options solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

12. How would you explain API Keys Security in API Development during an interview?intermediate

API Keys Security is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem api keys security solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

13. How would you explain OAuth2 Flow Basics in API Development during an interview?intermediate

OAuth2 Flow Basics is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem oauth2 flow basics solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for OAuth2 Flow Basics
{
  "route": "/api/v1/oauth2-flow-basics",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

14. How would you explain JWT Payload Token in API Development during an interview?intermediate

JWT Payload Token is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem jwt payload token solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

15. How would you explain CORS Policy Headers in API Development during an interview?intermediate

CORS Policy Headers is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem cors policy headers solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

16. How would you explain Rate Limiting Security in API Development during an interview?intermediate

Rate Limiting Security is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem rate limiting security solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for Rate Limiting Security
{
  "route": "/api/v1/rate-limiting-security",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

17. How would you explain Input Payload Validation in API Development during an interview?intermediate

Input Payload Validation is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem input payload validation solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

18. How would you explain Error Response Format in API Development during an interview?intermediate

Error Response Format is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem error response format solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

19. How would you explain API Versioning Strategy in API Development during an interview?intermediate

API Versioning Strategy is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem api versioning strategy solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for API Versioning Strategy
{
  "route": "/api/v1/api-versioning-strategy",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

20. How would you explain API Documentation Swagger in API Development during an interview?intermediate

API Documentation Swagger is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem api documentation swagger solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

21. How would you explain Testing APIs Postman in API Development during an interview?advanced

Testing APIs Postman is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem testing apis postman solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

22. How would you explain Mocking API Responses in API Development during an interview?advanced

Mocking API Responses is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem mocking api responses solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for Mocking API Responses
{
  "route": "/api/v1/mocking-api-responses",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

23. How would you explain GraphQL Basics in API Development during an interview?advanced

GraphQL Basics is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem graphql basics solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

24. How would you explain GraphQL Query Mutation in API Development during an interview?advanced

GraphQL Query Mutation is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem graphql query mutation solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

25. How would you explain Webhooks Push Pattern in API Development during an interview?advanced

Webhooks Push Pattern is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem webhooks push pattern solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for Webhooks Push Pattern
{
  "route": "/api/v1/webhooks-push-pattern",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

26. How would you explain gRPC Protocol Basics in API Development during an interview?advanced

gRPC Protocol Basics is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem grpc protocol basics solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

27. How would you explain API Gateway Pattern in API Development during an interview?advanced

API Gateway Pattern is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem api gateway pattern solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

28. How would you explain Caching API Responses in API Development during an interview?advanced

Caching API Responses is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem caching api responses solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

// API Specification for Caching API Responses
{
  "route": "/api/v1/caching-api-responses",
  "method": "POST",
  "contentType": "application/json",
  "response200": { "success": true }
}

29. How would you explain Best Practices in API Development during an interview?advanced

Best Practices is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem best practices solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.

30. How would you explain API Development Review in API Development during an interview?advanced

API Development Review is best explained with its purpose, a small example, and one common mistake.

Start by naming the problem api development review solves in API Development. Then show a short example, discuss the tradeoff, and mention how you would test it in a real codebase.