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beginner Phase · REST API Development

REST Principles

Master the six REST constraints.

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REST Design Principles

Resource-Oriented Design

Everything is a resource — an object with data and relationships.

Products  ──contains──>  Product  ──has──>  Review
                              │
                              +──has──>  Category

Key Principles

Principle Description Example
Identify resources Use nouns, not verbs /products not /getProducts
Use HTTP methods GET=read, POST=create, PUT=update, DELETE=remove GET /products/1
Representations Resources have multiple representations JSON, XML
Stateless No server-side session JWT token per request
Uniform interface Consistent URL patterns /resource/{id}

Good vs Bad API Design

# Bad (verb-oriented)
GET  /getUser?id=123
POST /createProduct
POST /deleteProduct?id=456

# Good (resource-oriented)
GET    /users/123
POST   /products
DELETE /products/456

Naming Conventions

Pattern Example Correct
Plural nouns /products Yes
Singular nouns /product No
Hyphenated /order-items Yes
camelCase /orderItems No
Nested resources /users/123/orders Yes

REST Best Practices

Principles

  • Stateless communication
  • Client-server separation
  • Cacheable responses
  • Uniform interface

HTTP Methods

  • GET: Read (idempotent, safe)
  • POST: Create
  • PUT: Full update (idempotent)
  • PATCH: Partial update
  • DELETE: Remove (idempotent)

Status Codes

  • 2xx: Success
  • 3xx: Redirection
  • 4xx: Client error
  • 5xx: Server error

Key Points

  • Understanding REST Design Principles 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 REST Design Principles

Design and implement a solution for REST Design Principles in a backend system. Consider scalability, error handling, and production readiness.

Solution 
// REST Design Principles implementation
// Key aspects: validation, error handling, logging, testing

public class RESTDesignPrinciples {
    // Production-ready implementation
}
REST Design Principles Edge Cases

Identify and handle edge cases for REST Design Principles. 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
REST Design Principles Testing Strategy

Write a testing strategy for REST Design Principles. 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. In REST, resources should be identified using:

Question 1 options

2. Which is a correctly designed REST URL?

Question 2 options

3. What is a common mistake when implementing REST Design Principles?

Question 3 options

Flashcards

Question

REST resource design rule

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Answer

Use nouns, not verbs. HTTP methods are the verbs.

Question

Should REST URLs be plural or singular?

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Answer

Always plural: /products, /users, /orders

Question

REST Design Principles 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. Everything is a resource — use nouns, not verbs
  • 2. HTTP methods define actions on resources
  • 3. Use plural nouns and consistent naming conventions
  • 4. Nested resources show relationships

Interview Tips

  • • Explain why /products is better than /getProducts
  • • Know plural vs singular noun conventions

Cheat Sheet

REST Design

  • Resources: Nouns, plural (/products)
  • Actions: HTTP methods (GET, POST, PUT, DELETE)
  • Naming: Hyphenated, lowercase (/order-items)
  • Nesting: /users/123/orders for relationships