An API gateway serves as an intermediary between backend services and users, facilitating communication and acting as a reverse proxy by routing client requests to appropriate microservices and returning aggregated responses. This system simplifies managing complex microservices architectures by providing features like analytics, version management, response bundling, monetization, caching, authentication, and security measures like rate-limiting. While API gateways enhance user experience by decoupling endpoints, enabling seamless updates, and improving performance, they can also become single points of failure or complicate routing logic as the application grows. To mitigate these issues, scaling API gateways horizontally and grouping microservices by client type and business logic are recommended strategies. The use of API gateways allows for protocol-rich application development and ensures the availability of services while maintaining performance and security.