What security function does an API Gateway primarily serve?

An API Gateway primarily serves as an access control mechanism by managing how clients interact with different backend services. It acts as a single point of entry into a system, enabling the implementation of authentication and authorization policies. This ensures that only valid and permitted requests reach the backend services, enhancing the overall security posture of the application.

In addition to access control, API Gateways often provide other functions, such as traffic monitoring and service routing, but their most critical role is to manage access effectively. This is achieved through mechanisms such as API keys, JSON Web Tokens (JWT), or OAuth tokens, which verify user identities and their permissions. By enforcing these access controls, an API Gateway helps to protect sensitive data and maintain system integrity against unauthorized access. Therefore, it plays a significant role in securing microservices and APIs, making access control its primary security function.