REST (Representational State Transfer) is an architectural style for designing networked applications. It uses standard HTTP methods like GET, POST, PUT, and DELETE to enable communication between clients and servers. RESTful APIs are stateless, meaning each request from a client contains all the information needed to process it. This approach simplifies interactions, enhances scalability, and is widely used in web services and mobile app development. REST also promotes a uniform interface, making it easier for developers to understand and use APIs securely. In cybersecurity, RESTful APIs must be properly secured to prevent unauthorized access and data breaches.