Summary
Starting a new project from scratch with a clean slate is one thing; tackling legacy systems with chaotic architectures is another. Many teams inherit systems described as “Monoliths” or “Big Balls of Mud,” and this workshop focuses on how to bring order to such challenges.
For who?
This workshop is created for software developers and software architects. You already have an understanding of fundamental DDD concepts like strategic design, tactical design, and ubiquitous language.
What you'll learn
Participants will learn how to evaluate their current systems and identify steps to introduce—or restore—structure. After an introduction to key principles, the workshop will explore three levels of transformation: tactical, socio-technical, and strategic. The Modularity Maturity Index (MMI) will guide teams to determine their best path forward, starting with a focus on understanding the domain. Using Collaborative Modelling, attendees will gain actionable insights to design a clear and future-ready architecture.
A mix of foundational theory and hands-on exercises will equip participants with practical strategies to address common challenges, such as BBOM architecture, anemic domain models, and disorganized teams. By the end of the workshop, attendees will have a catalogue of proven refactorings, actionable heuristics, and concrete tools to immediately evolve their own projects.
Schedule
- Opening story
- Introductory example
- Diagnosis of legacy software
- Strategic Transformation:
- Step 1: Domain re-discovery
- Step 1 exercise
- Step 2: Modelling the target architecture
- Step 3: Aligning current with target architecture
- Step 4: Do the move
- Tactical Transformation
- Team transformation
- Conclusion
What participants say
"The slides were great to follow—simple but therefore very good to understand. A few concepts are now clearer in my head and I have better arguments for what DDD is good for. In the short term, I'll ask myself what of the learned things we already use in our project and for what reason we may do things differently on purpose. Long term, the session has given me clarity on several concepts and better arguments for what DDD is good for."
- Benjamin Rosemeier, Maibornwolff GmbH - workshop participant 2025
"Really useful content with a great presentation by and discussions with Carola. I will share the approaches with my team and there are multiple principles we can apply. 9/10"
- Workshop participant 2025
Domain-Driven Transformation: Modernize Legacy Systems and Mitigate Risk
Written by Carola Lilienthal and Henning Schwentner - Published by O'Reilly
To prepare legacy software for the future, it's essential to modernize it. Domain-Driven Transformation provides an effective approach for transforming large legacy systems—either by breaking them into microservices or by converting them into maintainable modular monoliths.
In this guide, Carola Lilienthal and Henning Schwentner present their method, a comprehensive approach for transforming architecturally eroded software systems at the strategic, technical, and team organisational levels. You'll learn how to analyse business processes, break them down into bounded contexts, and apply domain-driven refactorings within Agile teams. Finally, this book offers guidance on designing the transformation process based on the current state of the existing architecture.
Packed with real-world examples and case-driven insights, you'll uncover the tools you need to build systems that scale, support business agility, and remain resilient over time.
- Assess your system's modularity and architectural health with the Modularity Maturity Index (MMI)
- Apply strategic and tactical domain-driven design (DDD) to manage complexity
- Reorganize and align your teams with Team Topologies
- Use EventStorming, domain storytelling, and Scenario Casting to clarify design
- Refactor incrementally with patterns that reduce risk while delivering value