In a RESTful architecture, what does stateless mean?

In a RESTful architecture, the term "stateless" means that the server does not store any application state between requests. Each request from the client to the server must contain all the information necessary for the server to fulfill that request, and the server treats each request as an independent transaction. This stateless design promotes scalability and reliability, as it allows the server to handle more requests without having to keep track of the state of each individual client.

By not maintaining state information, the server can efficiently allocate resources and avoid the complexities associated with session management. This approach also allows for easier load balancing and greater fault tolerance, since any server can handle requests without needing to remember past interactions.

The other choices present different interpretations of state management that contradict the foundational principles of REST. For instance, having the server actively managing application state is contrary to the stateless nature of REST. Similarly, requiring the client to manage all state or maintaining a persistent connection would violate the core principle of decoupling requests from individual states, effectively undermining the flexibility of the architecture.