By defining the interfaces between the microservices using well-defined APIs, it is possible to ensure that the microservices can communicate with each other in a predictable and reliable way.

 This makes it easier for developers to integrate the microservices into the application, and helps to ensure that the communication between the microservices is efficient and effective. 

https://learn.microsoft.com/en-us/azure/architecture/microservices/design/interservice-communication