How to break an 18 yo monolith - Andreas Bräu

Video from Devoxx Poland 2019. idealo.de launched in 2000 and started growing constantly: More features, more people, more and more lines of code. More than 50 developers in 6 teams worked on the same code base. The Software The software was designed as a Swiss Army knife for our company needs. At the end we've got a big monolith that is hard to maintain. Over the last years we had several approaches to extract some parts to reduce complexity. But very central parts, business functionality and the data model were never touched. The approach is centralized with a single database. The tech stack used is up-to-date, we have Java 11 with Spring Boot 2 and daily deployments. The Decision In 2018 we made a decision: remove the single, central database and create self-contained systems. Our main goals were: create independent and lightweight services have continuous deployments one service - one team teams are responsible for "their" services, from development to operations Answers What were our steps? How did we achieve our goals? What technologies did we use? What kind of cultural changes did we have?