What is REST in rest apis?

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It is an architectural style, not a protocol or standard, created by Roy Fielding in his doctoral dissertation in 2000. **Client-Server**: The client and server are separated concerns. The client handles the UI/UX; the server handles data storage and business logic. This separation allows each to evolve independently. This improves portability and scalability. **Stateless**: Every request from the client to the server must contain all the information needed to understand and process it. The server stores no session state between requests — each call is self-contained. This simplifies server design and improves reliability. **Cacheable**: Responses must label themselves as cacheable or non-cacheable. When cacheable, clients (and intermediaries) can reuse responses, reducing server load and improving performance. **Layered System**: The client doesn't need to know whether it's talking directly to the server or an intermediary (like a load balancer, cache, or gateway). Layers can be added or removed transparently, improving scalability and security. **Code on Demand (optional)**: Servers can extend client functionality by transferring executable code (like JavaScript) to run on the client. This is the only optional constraint in REST. **Uniform Interface**: A consistent, standardized interface between components simplifies the architecture. This is achieved through four sub-constraints: resource identification in requests (URIs), resource manipulation through representations, self-descriptive messages, and hypermedia as the engine of application state (HATEOAS). The cornerstone of REST, this constraint simplifies and decouples the architecture through four interface constraints: resource identification, resource manipulation through representations, self-descriptive messages, and hypermedia as the engine of application state (HATEOAS). // RESTful API for a blog

// GET /api/posts - List all blog posts
GET https://api.example.com/api/posts

// GET /api/posts/123 - Retrieve specific post
GET https://api.example.com/api/posts/123

// POST /api/posts - Create a new post
POST https://api.example.com/api/posts
Content-Type: application/json

{
  "title": "My First Post",
  "content": "This is the content...",
  "author": "john@example.com"
}

// PUT /api/posts/123 - Update entire post
PUT https://api.example.com/api/posts/123
Content-Type: application/json

{
  "title": "Updated Title",
  "content": "Updated content...",
  "author": "john@example.com"
}

// PATCH /api/posts/123 - Partially update post
PATCH https://api.example.com/api/posts/123
Content-Type: application/json

{
  "title": "New Title Only"
}

// DELETE /api/posts/123 - Delete post
DELETE https://api.example.com/api/posts/123 **Resources**: Everything in REST is a resource, which is any information that can be named (users, documents, images). Resources are identified by URIs (Uniform Resource Identifiers). **HTTP Methods**: REST uses HTTP methods to perform operations on resources: GET (retrieve), POST (create), PUT (full update), PATCH (partial update), DELETE (remove). **Representations**: Resources are manipulated through representations (JSON, XML, HTML). The client and server exchange these representations, not the actual resource itself. **Stateless Communication**: Each request is independent; no client context is stored on the server between requests. All state required to process the request is included in the request itself. **Hypermedia (HATEOAS)**: Hypermedia as the Engine of Application State means that responses contain links to related resources, allowing the client to discover available actions dynamically. Use nouns in URLs (not verbs): `/api/users` not `/api/getUsers` Use plural nouns for collections: `/api/products` rather than `/api/product` Use HTTP status codes correctly: 200 OK, 201 Created, 400 Bad Request, 401 Unauthorized, 404 Not Found, 500 Internal Server Error Version your API: `/api/v1/users` to allow for future changes without breaking existing clients Use query parameters for filtering, sorting, and pagination: `/api/posts?status=published&sort=-createdAt&page=2&limit=20` Return appropriate error messages with consistent structure Use SSL/TLS (HTTPS) for all communications The key insight of REST is that it treats the web as a distributed hypermedia system. Resources are identified by URIs, manipulated through their representations, and linked together through hypermedia. When a REST API is fully hypermedia-driven (HATEOAS), clients need only know the initial entry point; all subsequent actions are discovered through links in the responses. This reduces coupling between client and server and allows the API to evolve without breaking clients.

What is REST in rest apis?

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