Can you explain the main principles of RESTful API architecture?

RESTful API is built on several key principles:

• Client-server architecture: the client and server are separated, allowing independent development.
• Statelessness: each request from the client 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: using standard HTTP methods (GET, POST, PUT, DELETE) and clearly defining resources via URLs.
• Layered system: architecture can have multiple layers (proxies, load balancers, etc.) without affecting client-server interaction.
• Code on demand (optional): the server can send executable code to the client.

Example URLs and methods:

GET /users/123    // get user with ID 123
POST /users       // create a new user
PUT /users/123    // update user data
DELETE /users/123 // delete user