What does the term "API gateway" refer to?

The term "API gateway" specifically refers to a server that acts as a mediator or intermediary between clients and various backend services. It manages and routes API requests, simplifying the communication process by providing a single entry point into the system. This allows the gateway to handle requests from clients, direct those requests to the appropriate service, and consolidate responses before sending them back to the clients.

Additionally, an API gateway often provides functionalities such as rate limiting, caching, and monitoring, enhancing the overall efficiency and performance of API interactions.

The other options represent concepts related to web services but do not accurately define an API gateway. While centralized authentication servers and methods for securing data transfer are crucial in the context of APIs, they do not encompass the broader role of managing and routing requests, which is the primary function of an API gateway. Similarly, a database for storing API data is unrelated to the routing or management aspect of API requests.