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What is REST API?

REST (Representational State Transfer) is an architectural style for designing networked applications. REST APIs use HTTP methods to perform CRUD operations and communicate between clients and servers in a stateless manner. REST API Authentication Methods

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Core Principles of REST

REST is built on six fundamental principles that ensure scalability and maintainability:
1

Client-Server Architecture

Separation of concerns between the user interface (client) and data storage (server), allowing independent evolution of both components.
2

Stateless Communication

Each request from client to server must contain all information needed to understand and process the request. The server stores no client context between requests.
3

Cacheability

Responses must define themselves as cacheable or non-cacheable to improve performance and scalability.
4

Uniform Interface

Standardized way of communicating between client and server through resource identification, manipulation through representations, and self-descriptive messages.
5

Layered System

Architecture can be composed of hierarchical layers, with each component only interacting with its immediate layer.
6

Code on Demand (Optional)

Servers can extend client functionality by transferring executable code.

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HTTP Methods

HTTP Request Methods REST APIs leverage standard HTTP methods for operations: 
GET /api/users/123
Host: example.com

# Retrieves a resource from the server
# Idempotent - multiple identical requests return the same result

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Additional HTTP Methods

  • HEAD: Returns response headers without the body (useful for checking if a resource exists)
  • OPTIONS: Describes communication options for the target resource
  • CONNECT: Establishes a tunnel to the server
  • TRACE: Performs a message loop-back test

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HTTP Status Codes

HTTP Status Codes HTTP status codes are divided into five categories:
CategoryRangeDescriptionCommon Examples
Informational100-199Request received, continuing process100 Continue, 101 Switching Protocols
Success200-299Request successfully received and processed200 OK, 201 Created, 204 No Content
Redirection300-399Further action needed to complete request301 Moved Permanently, 302 Found, 304 Not Modified
Client Error400-499Request contains errors or cannot be fulfilled400 Bad Request, 401 Unauthorized, 404 Not Found
Server Error500-599Server failed to fulfill valid request500 Internal Server Error, 502 Bad Gateway, 503 Service Unavailable

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REST API Design Best Practices

REST API Cheatsheet

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8 Essential Tips for Efficient API Design

Tips for RESTful API Design
1

Domain Model Driven

Design your path structure based on your domain model for intuitive resource organization.
/api/users/{userId}/orders/{orderId}/items
2

Choose Proper HTTP Methods

Use standard HTTP methods consistently. Avoid overcomplicating with methods like PATCH unless necessary.
3

Implement Idempotence Properly

GET, PUT, and DELETE are naturally idempotent. Design POST operations to be idempotent when possible for improved robustness.
4

Use Appropriate Status Codes

Define a limited, consistent set of HTTP status codes to simplify client development.
5

API Versioning

Plan versioning strategy from the start to handle future changes gracefully.
/api/v1/users
/api/v2/users
6

Semantic Paths

Use clear, self-documenting paths that make APIs easy to understand.
Good: /api/users/123/orders
Bad:  /api/getUserOrders?id=123
7

Batch Processing

Use keywords like batch or bulk at the end of paths for batch operations.
POST /api/users/batch
DELETE /api/orders/bulk
8

Query Language

Design flexible query rules for pagination, sorting, and filtering.
GET /api/users?page=2&limit=20&sort=name&filter=active:true

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API Security

API Design Security

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Authentication Methods

Common authentication approaches for REST APIs:
  • API Keys: Simple tokens passed in headers or query parameters
  • OAuth 2.0: Industry-standard protocol for authorization
  • JWT (JSON Web Tokens): Stateless authentication with encoded user information
  • Basic Auth: Username and password encoded in Base64 (use only over HTTPS)

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Security Best Practices

Always use HTTPS to encrypt data in transit and protect against man-in-the-middle attacks.
  • Include authentication credentials in every request
  • Add timestamps to prevent replay attacks
  • Use nonces (random strings) to ensure request uniqueness
  • Implement rate limiting to prevent abuse
  • Validate all input data
  • Never expose sensitive data in URLs

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Performance Optimization

API Performance Optimization

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Top 5 Ways to Improve API Performance

1

Result Pagination

Stream large result sets back to clients in manageable chunks.
{
  "data": [...],
  "page": 1,
  "totalPages": 10,
  "totalItems": 200
}
2

Asynchronous Logging

Send logs to lock-free buffers and flush periodically to reduce I/O overhead.
3

Data Caching

Cache frequently accessed data in memory (e.g., Redis) for faster retrieval.
4

Payload Compression

Compress requests and responses using gzip or brotli to reduce transmission time.
5

Connection Pooling

Maintain a pool of database connections to eliminate connection overhead.

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REST vs GraphQL

REST vs GraphQL

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When to Use REST

  • Simple, uniform interfaces between services
  • Straightforward caching requirements
  • Well-defined resource structure
  • Public APIs with broad client types

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When to Consider GraphQL

  • Complex frontend data requirements
  • Need to aggregate data from multiple sources
  • Rapidly evolving client needs
  • Mobile applications requiring precise data fetching
REST excels with simple, consistent contracts, while GraphQL shines with complex, frequently changing frontend requirements.

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API Style Comparison

API Styles Comparison REST is one of several API architectural styles, each with specific use cases:
  • SOAP: Enterprise applications requiring strict contracts and transactions
  • REST: Web services, public APIs, microservices
  • GraphQL: Complex data requirements, mobile applications
  • gRPC: High-performance microservices, real-time communication

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Practical Examples

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Complete User Management API

GET /api/v1/users?page=1&limit=20&sort=createdAt:desc HTTP/1.1
Host: api.example.com
Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
Accept: application/json

Response: 200 OK
{
  "data": [
    {
      "id": "123",
      "name": "John Doe",
      "email": "[email protected]",
      "createdAt": "2024-01-15T10:30:00Z"
    }
  ],
  "pagination": {
    "page": 1,
    "limit": 20,
    "totalPages": 5,
    "totalItems": 95
  }
}

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Key Takeaways

REST APIs remain the most popular choice for web services due to their simplicity, scalability, and compatibility with HTTP infrastructure.
  • REST uses standard HTTP methods and status codes for intuitive API design
  • Stateless architecture improves scalability and reliability
  • Proper design patterns and security practices are essential
  • Performance optimization through caching, compression, and pagination
  • Choose REST for straightforward, cacheable, resource-based APIs

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