What best describes a REST API's purpose?

The purpose of a REST API is best described by defining standards for how web-based systems interact. REST, which stands for Representational State Transfer, is an architectural style that utilizes standard HTTP methods such as GET, POST, PUT, and DELETE to enable communication between clients and servers. It emphasizes a stateless communication protocol and the use of resources, allowing for scalable and loosely coupled web services.

By establishing these standards, REST APIs facilitate interoperability and allow different systems to understand each other, simplifying the processes of creating, reading, updating, and deleting data over the web. This promotes an efficient way to expose and consume web services, making it easier for developers to build applications that can interact seamlessly with various web resources.

While securing data communications, enhancing graphical user interfaces, and managing hardware resources can be important aspects of web development and network management, they do not specifically capture the essence of what REST APIs are fundamentally designed to do. Their primary role is about defining how applications communicate using established web protocols and standards.