Advanced CQRS Implementation: Event Sourcing, Multiple Databases, Messaging and Integration in Real-World Microservices

Today, we are going to explore one of the most complex variants of CQRS. With multiple databases, event sourcing, messaging and integrations. This implementation is suitable for complex and scalable systems under a huge load.

I am talking about systems like: Amazon, Netflix, Atlassian and more …

For the basic theory and the simple CQRS variant implementation, please check out my previous article.

CQRS Simplified — Explained and implemented

CQRS complex variant flow and components

Let’s check the flow and components in this CQRS variant

There are following components:

• API client — it can be a front-end application or other service in the case of service-to-service communication.