REST is a stateless architectural style for building application programming interfaces (APIs) that follows constraints and principles to ensure understanding between applications on the Internet. It's characterized by unidirectional communication, where the server only gives data when requested. In contrast, WebSocket is a two-way communication channel with a server, enabling both sending messages to the server and receiving event-driven messages back. WebSocket is a communications protocol that uses HTTP links, whereas REST is a style of building APIs. While REST is simple and easy to use, WebSocket offers performance gains over REST in certain cases due to its stateful nature. However, using WebSockets for simple applications can complicate the development process. REST is well-suited for isolated, occasional communications, such as creating basic APIs or GET requests, whereas WebSocket is ideal for real-time interaction and sending events back to users. Ultimately, deciding between REST and WebSocket depends on the specific needs of the project, with REST being the most common choice for simple web projects and WebSockets being better suited for applications requiring real-time information exchange.