Throughout my fifteen-plus years as a software architect, one question has often come up regarding microservices: How large is “micro”?

Or, expanded: How many microservices should a system consist of, and what responsibility should each one have?

In this talk you will learn about the history of microservices, the difference between a microservice architecture and a monolithic one, the relation between microservices and Domain-Driven Design, and – based on all of these – my answer to this question.

I will also discuss recurring uncertainties around data ownership and storage, and explain how to make sure there is still a path forward when it turns out the decision on size or quantity is wrong – even if it was correct at the time it was made.