How to distinguish REST API from WebSocket and what is their main difference?

REST API is an architectural style for creating web services that uses HTTP requests (GET, POST, PUT, DELETE) to interact with the server. Each interaction is a separate request and response, meaning the connection is essentially one-time and stateless.

WebSocket is a protocol for bidirectional persistent communication between the client and server. After establishing a WebSocket connection, the client and server can exchange messages in real-time without re-establishing the connection.

Main difference:

• REST API — request-response, each interaction is separate.
• WebSocket — a persistent connection for real-time data exchange.

Example:

• REST API: the client requests a list of users, the server responds, and the connection is closed.
• WebSocket: the client connects to the server and receives updates about new users immediately after they appear.