What is a RESTful API?

A RESTful API, which stands for Representational State Transfer Application Programming Interface, fundamentally revolves around an architectural style that is designed for networked applications. This style is integral in how systems communicate over the internet, emphasizing a stateless request-response model. In this model, every request from a client to a server must contain all the information the server needs to fulfill that request, making the interactions between client and server more efficient and scalable.

This approach is grounded in standard HTTP methods like GET, POST, PUT, and DELETE, which correspond to fetching, creating, updating, and deleting resources, respectively. By adhering to these principles, RESTful APIs enable the seamless integration and operation of distributed systems, promoting loose coupling and making it easier to build and maintain web services.

The other options do not provide the right context or definition for what a RESTful API is. For example, a programming language is distinct from the field of API design, while a database management system deals with data storage and retrieval, not network communication protocols. Similarly, a web hosting service is related to the deployment of applications on the internet, rather than the specifications or architectural styles for how these applications communicate with one another.