RESTful is an architectural style for designing networked applications. It stands for Representational State Transfer and uses standard HTTP methods like GET, POST, PUT, and DELETE to interact with resources. These resources are identified by unique URLs, making it easy to access and manipulate data over the web. In a RESTful system, data is typically represented in formats like JSON or XML. This approach promotes scalability and simplicity, allowing developers to build services that can be easily consumed by various clients, such as web browsers or mobile applications.