Microservices have to be integrated, and they need to communicate. This can be achieved at different levels (see Figure 8.1). Each approach has certain advantages and disadvantages, and at each level different technical implementations of integration are possible.
• Microservices contain a graphical user interface. This means that microservices can be integrated at the UI level. This type of integration is introduced in section 8.1.
• Finally, integration can be performed at the database level using data replication (