What does an API proxy application NOT do?

An API proxy acts as an intermediary between clients and the backend services, handling various aspects of API management such as traffic monitoring, security, transformation, and governance.

The role of an API proxy primarily revolves around managing the requests and responses flowing to and from the backend services. It does this by allowing or denying requests based on defined policies and conditions. Therefore, the proxy is responsible for determining which request Mule event can pass through to the API backend service. Additionally, it meters the traffic that flows through it thereby providing insights into usage patterns and performance, and applies runtime policies to enforce governance objectives such as rate limiting, access control, and security measures.

However, the specific functionality of determining which response Mule event is allowed to pass through to the API backend service is not typically a role of the proxy. Instead, this logic and filtering often occur directly within the backend services or external systems, focusing instead on controlling incoming requests primarily rather than filtering outgoing responses. Thus, saying that an API proxy does not determine which responses are passed through to the backend aligns with its primary functions focused on managing requests rather than responses.