What is the role of an API gateway in a microservices architecture used in MIPC?

• A. An API gateway stores data for all microservices.
• B. An API gateway compiles code for deployment.
• C. An API gateway serves as a firewall at the network edge only.
• D. An API gateway handles ingress, routing, authentication, rate limiting, circuit breaking, load balancing, and observability for a set of microservices.

Answer: (D)

The API gateway acts as the single entry point into a microservices system, coordinating how external clients reach the various services behind it. It sits at the edge and handles ingress, deciding which service should handle a given request and efficiently routing or load balancing that traffic across multiple instances. Beyond routing, it enforces cross-cutting policies like authentication and authorization, rate limiting to protect backends from abuse, and circuit breaking to prevent a failing service from taking down others. It also provides observability through metrics and traces so you can monitor performance and reliability.

This role goes well beyond a simple firewall or a data store. It doesn’t store data for all microservices, nor does it compile code for deployment. And while it can enforce security at the edge, its primary value is in managing, securing, and observing traffic across the entire set of microservices, enabling resilient, scalable communication between clients and services.