Can you explain the main principles of REST architecture and how they are implemented in API development?

REST (Representational State Transfer) is an architectural style for creating web services based on a set of principles:

• Client-server architecture: clients and servers are separated, simplifying development and scaling.
• Stateless: each request from a client to a server must contain all the information needed; the server does not store state between requests.
• Caching: responses can be cached to improve performance.
• Uniform interface: using standard HTTP methods (GET, POST, PUT, DELETE) for resource operations.
• Resource identification via URI: each resource has a unique address.
• Layered system: architecture can consist of multiple layers, such as proxies and gateways.

When developing REST APIs, these principles are implemented as follows:

• Resources (e.g., users, products) are represented as URLs, e.g., /users/123.
• HTTP methods are used: GET for retrieving, POST for creating, PUT/PATCH for updating, DELETE for deleting.
• The server does not store sessions; all data for processing requests are passed to it.
• Responses may include headers for caching.
• Data formats are usually JSON or XML.

Example request to get a user:

GET /users/123 HTTP/1.1
Host: example.com
Accept: application/json

Response:

{
  "id": 123,
  "name": "Ivan Ivanov"
}