Microservices must communicate using an inter-process communication mechanism. In this chapter, we have learned about the multiple approaches for inter-service communication. We have discussed two approaches: the synchronous communication style and the asynchronous communication style. We then discussed one-to-one inter-service communication, which uses a single receiver, and one-to-many inter-service communication, which uses multiple receivers. After that, we looked at various technologies that provide inter-service communication mechanisms.
In the next chapter, Service Registry and Discovery, we'll discuss how to use the External API Gateway to provide extended flexibility, an approach that calls services and variations, patterns, and use cases.