On what principle is REST API based and what are the main concepts it uses?

REST API is based on the principles of the REST (Representational State Transfer) architectural style. Main concepts:

• Client-server architecture: clients and servers are separated, allowing independent development.

• Stateless: each request from the client to the server must contain all the necessary information; the server does not store client state between requests.

• Caching: responses can be cached to improve performance.

• Uniform interface: interaction occurs through standardized HTTP methods (GET, POST, PUT, DELETE, etc.).

• Resource identification: resources are identified by URIs.

• Resource representations: the client receives a representation of the resource (e.g., JSON or XML).

Examples of main HTTP methods in REST API:

• GET — retrieve a resource
• POST — create a resource
• PUT — update a resource
• DELETE — delete a resource

Thus, REST API is built around resources and operations on them via standard HTTP methods, ensuring simplicity and scalability.