Another important feature of the design architecture in building microservices is studying and analyzing their behavior to each other when it comes to data exchange. Chapter 9, Spring Boot 2.0, established the conclusion that asynchronous, reactive, and blocking microservices work by exposing REST services that can be consumed by client applications. Although there is decoupling in the architectural design pattern, a microservice still has direct control over its clients because of the endpoint consumption occurring during the process. This gray area can still be considered to be tightly coupled behavior but to a minor degree. To implement a totally decoupled microservice, this recipe will introduce a new protocol that can initiate microservices to communicate synchronously with its clients without any endpoint intervention.