Introduction
Microservice architecture consists of a suite of independently deployable, small, modular, and compassable (composable) services. Each service runs a unique process and communicates through a well-defined, lightweight mechanism to serve a business goal.
In addition to modular services, the API gateway and other elements are integral parts of microservice architecture.
What and Why of API Gateways
Basically, the API Gateway is a reverse proxy to microservices and acts as a single-entry point into the system. It is similar to a Facade pattern from object-oriented design and similar to the notion of an “Anti-Corruption Layer” in Domain Driven Design.
With a single-entry point into the system (references), it becomes easy (and manageable) to enforce runtime governance such as common security requirements, common design decisions (e.g. every consumer of the service should have X-Correlation-ID header), and real-time policies such as monitoring, auditing and measuring API usage, and throttling.
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