Explain the principle of operation of RESTful API and its main features

RESTful API is an architectural style for creating web services based on REST (Representational State Transfer) principles. The main idea is to use standard HTTP methods (GET, POST, PUT, DELETE, etc.) to interact with resources identified by unique URLs.

Key features of RESTful API:

• Resource-oriented: all data is represented as resources with unique URIs.
• Use of standard HTTP methods: for example, GET to retrieve data, POST to create, PUT to update, DELETE to delete.
• HTTP status codes: to inform the client about the result of the request (e.g., 200 OK, 404 Not Found).
• Stateless: each request contains all the necessary information; the server does not store client state between requests.
• Caching: responses can be cached to improve performance.

Example: a GET request to /users/123 will return data for the user with ID 123.