Which message exchange method between microservices is preferable: synchronous or asynchronous?

The choice between synchronous and asynchronous message exchange between microservices depends on system requirements.

• Synchronous exchange is suitable when an immediate response is needed and strict operation order must be maintained. However, it increases service coupling and can lead to delays if one of the services is unavailable.

• Asynchronous exchange is more flexible and resilient to failures, as services interact through message queues or brokers without expecting an instant response. This improves scalability and fault tolerance.

In most modern distributed systems, it is preferable to use asynchronous exchange, especially if scalability and fault tolerance are important. Synchronous exchange is applicable when immediate reaction and strict sequence are required.