DDD Europe 2023 - Program

EventStorming, from Knowledge to Working Domain Model

Pre-conference Workshops



Nico Krijnen and Jettro Coenradie

Nico KrijnenJettro Coenradie
June 7

Two brains, one domain, one laptop, and a guarantee for a day of fun and learning. You’ll go back to basics. Talking about the domain, exploring it using EventStorming with a small group and then pair up to design and code the model.


The day starts with an EventStorming session to explore an interesting domain. You will work in small groups, making sure everyone in the group guards a portion of the EventStorming session by taking on specific roles. But we won't stop after we've explored the domain. During the second part of the day you will work in pairs, together with other participants. You will use the output of the EventStorming session and all the knowledge that you've gathered about the domain. Together, you'll play around, modeling parts of the domain in code, using tests to guide your design. You can choose from several starter templates, to help you code the domain using different approaches. From a typical object oriented domain model to an event sourced domain model. Throughout the workshop, pairs will share their approach so we can all learn from each other.

All you have to bring is a laptop with a recent version of IntelliJ installed (only one laptop per pair is needed). Java or Kotlin templates will be provided, or you can choose to use your own preferred stack.

What you will learn:

  • Why you need to start by understanding the problem and exploring a domain before you start coding.
  • How to 'sketch' in code and tease out a model bit by bit.
  • Not to be afraid to throw away the model and sketch again.
  • That there are many ways to implement a model and that there are tradeoffs to make when choosing an approach.

Especially the part where pairs share and explain their approach is really insightful and helps to realize that there are many (good) solutions to a problem. It also creates a lot of interaction between participants which always makes for many views being shared and for lively discussions.


Bring a laptop and make sure you install IntelliJ on it beforehand so you can have a running start.

About Nico Krijnen

Nico Krijnen is a Cloud Solution Architect at Luminis. He helps organizations to translate available options into practical solutions for complex problems. For a big chunk of his career, he disrupted the DAM space by building an innovative visual file management solution called Elvis, which is being used by media organizations all over the world. Besides leading teams and giving direction, he likes to roll up his sleeves and experience first-hand how (and whether) the latest technologies work in the real world. He is never shy of making unconventional choices to achieve radical results.

Recordings: https://youtube.com/playlist?list=PLpsPwCgJlHhyONy7_4fb-AfYcmAS0oD7P Slides: https://speakerdeck.com/nicokrijnen

About Jettro Coenradie

Jettro is a software architect, search relevance geek, and data enthusiast that loves to talk about his job, hobbies, and other things that inspire people. Jettro truly believes in the Luminis mantra that the only thing that grows by sharing is knowledge. After more than ten years of creating the best search engines for multiple customers, Jettro is drawn into Machine Learning and Natural Language Processing. Learning and talking about NLP is what drives him to keep improving the user experience of search engines.