Explain the principles and main ideology of RESTful API.

RESTful API is an architectural style for creating web services based on REST (Representational State Transfer) principles. Key ideas:

• Resources: Everything the API works with is represented as resources (e.g., users, products), which are identified by unique URIs.

• HTTP Methods: Standard HTTP methods are used to interact with resources:

  • GET — retrieve resource data;
  • POST — create a new resource;
  • PUT — update a resource;
  • DELETE — delete a resource.

• Status Codes: Server responses contain HTTP status codes indicating the result of the operation (e.g., 200 OK, 404 Not Found).

• Stateless: Each client request to the server must contain all the information needed to process it; the server does not store state between requests.

• Caching: Responses can be cached to improve performance.

• Uniform Interface: Simplifies interaction and understanding of the API.

Example of a request to a RESTful API to get a list of users:

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

Response:

[
  {"id": 1, "name": "Ivan"},
  {"id": 2, "name": "Maria"}
]

Thus, RESTful API provides a simple, understandable, and standardized way for client-server interaction.