In this talk Kacper will take you on a journey during which he will reflect on his experience with replacing a complex loyalty system and challenges the project faced. He will share with the audience his thoughts on what worked, what could have been done differently and what caused problems. You will learn how to make best use of Domain Experts and explain why consistency is a business problem. Try to answer if it’s possible to stay sane in the Microservice world and discuss challenges arising when trying to migrate from CRUD persistence to Event Sourcing.