How does Envoy serve as an API gateway?

Envoy functions as an API gateway by effectively managing traffic between clients and services, enforcing security policies, and providing monitoring capabilities for APIs. It acts as a centralized point that can handle incoming requests, directing them to the appropriate backend services while ensuring that traffic is load balanced and secure.

One key aspect of this role is the enforcement of security policies, which can include authentication, authorization, and rate limiting to protect both the services and the data being transmitted. Moreover, Envoy provides features for observability, such as logging, metrics, and tracing, which enable developers and operators to monitor the health and performance of their applications effectively.

While the other choices may represent functionalities related to APIs, they do not capture the primary responsibilities of an API gateway. For instance, data storage capabilities and serving static content do not typically fall under the purview of an API gateway, nor do they relate to the core aspects of traffic management and security that Envoy specializes in. Transforming data formats is also a useful capability, but it is not the main function of an API gateway, which focuses more on interacting with and managing requests than on modifying data formats.