The need for an API Gateway pattern
In the microservices architecture, lots of API services work together for the distributed application. There could be more than 100 API services and UI components talking to each other for a business goal. So, these UI components must know about all microservices endpoints with a port to call these API services if you are not using API Gateway.
An API Gateway mechanism is required when you want to implement the common aspects for your distributed application, such as CORS, authentication, security, and monitoring, in terms of this design. If you are not using API Gateway, then you have to implement these aspects into all API services, so the same code will be repeated over all microservices. To avoid this problem, we have to use a common service or entry point where all common aspect code is written and the client will call that common service.
Let's see the following diagram of a distributed application without an API Gateway service:
As you can see, each...
