This whitepaper explains the basic concepts of DDD, CQRS and Event Sourcing. It explores common misunderstandings and how the Axon platform helps by providing the foundation for building asynchronous message-driven systems based on the concepts of microservices, event-driven architecture, and event sourcing. By using the same basic concepts and ideas, Axon also supports developing applications that begin as a monolith and later evolve into event-driven microservices, without significant refactoring as the requirements change.

This whitepaper covers:

• Monolith

• Microservices

• Event-Driven Architecture

• Events and messages

• Eventual Consistency

• Event sourcing

• Location transparency

• Events and messages

• Splitting up the architecture

• Axon

• Axon Framework

• Axon Server