- Only then get out the legacy system and see where its current architecture aligns with the target architecture and where changes have to be made.

- From this domain knowledge you will be able to derive the target architecture.

- So, the first step is to (re-)understand the domain, i.e. the business and its processes.

The best way to split a monolith is to first put that monolith aside. It might be counterintuitive, but before you decompose the legacy system, it is important to understand what the problem is that the system was built for.

domain-driven-transformation.com

Yes, it grew about 150 pages :-)

🙂

Thank you!

- And last but not least to our families. You are the best; this wouldn't have been possible without you!

- To Sergio Morazán, @suksr.bsky.social, Philipp Kostyra, @tekiegirl.bsky.social, @gienverschatse.com, and Joe Yoder for their terrific endorsements
- To Michele Cronin and Louise Corrigan, our editors at @oreilly.bsky.social

- To James Higginbotham, Stefan Hofer, @vladikk.bsky.social, Mufrid Krilic, Sönke Magnussen, @bitboss.bsky.social, @nick-tune.me, @vaughnvernon.bsky.social, Rebecca Wirfs-Brock, and Eoin Woods for their reviews that improved the text so much

This is the moment to say thank you:

- To Michael Feathers for an amazing foreword
- To @ziobrando.bsky.social and Jörn Koch for their contributions to the Collaborative Modeling chapter

Our goal with this book is to be helpful when you have to deal with what is called a Monolith or Big Ball of Mud. We describe how to combine Domain-Driven Design, Team Topologies, Modularity Maturity Index, EventStorming, Domain Storytelling and other tools to refactor legacy software.

Cover of the bool Domain-Driven Tranformation featuring an Atlas Moth

It has been quite an odyssey, but now it is finally here:

📣 📚 Domain-Driven Transformation: Modernize Legacy Systems and Mitigate Risk 📚 📣

In this book, Carola Lilienthal and I present our approach to transform architecturally eroded systems.

domain-driven-transformation.com

Modern Software Architecture with the Architecture Hamburger, Wed, Mar 26, 2025, 5:30 PM | Meetup Hello everyone, We have an exciting meetup coming up for you! Henning Schwentner from WPS, also one of the co-organizers of ComoCamp, is going to join us to talk about Mod

Servus Vienna! I’m happy to announce that I’m going to speak at the Softwarearchitektur Wien meetup on March 26. If you want to learn about “Modern Software Architecture with the Architecture Hamburger” please join: www.meetup.com/softwarearch...

@stefantoth.bsky.social #softwarearchitecture #🍔

Domain-Driven Transformation with Henning Schwentner, Mo., 3. Feb. 2025, 18:30 | Meetup We will meet at 6:30pm at TESTIFI GmbH for drinks and pizza. The talk starts at 7:00pm and will be in English. **Henning Schwentner: Domain-Driven Transformation — How to B

Looking forward to be speaking at Microservices Meetup Munich next week. Join if you like to learn about Domain-Driven Transformation.

www.meetup.com/de-DE/micros...

#dddesign #microservices #softwarearchitecture #legacycode

Global DDD Day in Hamburg: Domain-Driven Transformation (Henning Schwentner), Do., 21. Nov. 2024, 18:00 | Meetup **💥Special Edition celebrating the [Global Domain-Driven Day 2024](https://virtualddd.com/open-space/global-domain-driven-days-2024/)💥** **📜Timetable📜** * 18:00h Welc

Moin Hamburg! On the 21st of November there will be a local DDD meetup on Domain-Driven Transformation with @hschwentner.bsky.social. He will present a catalog of refactorings that help cure: BBOM architecture, anemic domain models, and badly organized teams.

RSVP here:

Global DDD Day in Hamburg: Domain-Driven Transformation (Henning Schwentner), Do., 21. Nov. 2024, 18:00 | Meetup **💥Special Edition celebrating the [Global Domain-Driven Day 2024](https://virtualddd.com/open-space/global-domain-driven-days-2024/)💥** **📜Timetable📜** * 18:00h Welc

📣New DDD Hamburg Meetup📣

On Nov 21 we’re celebrating the Global Domain-Driven Day 2024 (lnkd.in/gNxhxHdb) with a session on Domain-Driven Transformation.

@kenny.weave-it.org @heimeshoff.bsky.social @mentrix.bsky.social @maxsc.bsky.social for the initiative!

www.meetup.com/de-DE/ddd-hh...

Thanks Sönke! Glad that the book helps. Carola and I are currently working with @vaughnvernon.bsky.social on the English edition.

ComoCamp 2024 The ComoCamp is the unconference reaching out to bring practitioners of collaborative modeling methods together with their creators and thought leaders.

With a couple of friends from the community, I’m organizing the ComoCamp—an unconference that brings together the makers and  masters of collaborative modeling methods like #EventStorming, #UserStoryMapping, and #DomainStorytelling.
 
@selketjah.bsky.social @ewolff.com
 
comocamp.org

Explore DDD Conference - 2024 Explore DDD Conference - 2024: Domain-Driven Design Conference in Denver, Colorado, USA for Software Leaders. Practical, cutting-edge, talks & workshops.

The organizers have created an inspiring and fun space to explore systems design here in the US. I've missed gathering here and can't wait to get to Denver on March 12th. Check out the schedule and pre-conference offerings.

https://exploreddd.com/

On February 14, DDD Hamburg Meetup welcomes @carolali speaking about “Fighting Technical Debt with DDD.” Thanks, Kai Rüstmann and Falco Wehber from SIGNAL IDUNA for hosting! #dddhamburg #dddesing #softwarearchitecture www.meetup.com/de-DE/ddd-hh...

ComoCamp is back! We just opened our ticket shop. Join us in Vienna, May 6–8 2024! Register at comocamp.org 🎉🥳🎫

Happy to restart #DDDHamburg with “Introduction to DDD—It’s All About the Domain, Honey” on Dec 6!

We look on the foundations of Domain-Driven Design, but it’s also a gathering of the community. Plus: pizza and Glühwein 🍕🎅🏼🍷

Repost appreciated :-)

#DDDesign www.meetup.com/ddd-hh-domai...

Kaffee-Buffet, im Hintergrund die Elbphilharmonie

Coffee with a view 🥰
Gleich geht's los mit der WPS software@work-Konferenz
#sawconf

Video from the talk @hschwentner.bsky.social and I gave at #DDDeu on FP vs. DDD is up. Loving the comment section already! www.youtube.com/watch?v=3nkw...

When @hofstef and I wrote “Domain Storytelling,” we worked hard to push out all the errata. Inevitably, some still slipped through and we collect them at domainstorytelling.org/book

If you find more, help us and create a pull request on the website!

#DomainStorytelling #DDDesign

Happy to restart #DDDHamburg with “Introduction to DDD—It’s All About the Domain, Honey” on Dec 6!

We look on the foundations of Domain-Driven Design, but it’s also a gathering of the community. Plus: pizza and Glühwein 🍕🎅🏼🍷

Repost appreciated :-)

#DDDesign www.meetup.com/ddd-hh-domai...

As a first activity, I’m planning the next session on December 6 as a real life meeting with a talk and some glühwein. As a restart after the years of the pandemic the talk will be an introduction to DDD. Details will follow soon. It would be terrific to see you there! 4/4

Thanks also to Virgilio Lino for kicking off the meetup back in 2016, and to Hauke Stange for supporting as co-organizer. 3/4

In the last couple of years Ulrich Schmidt-Goertz served as the organizer of the meetup DDD Hamburg and has hosted many awesome sessions with both local and international speakers like Jimmy Nilsson, @mathiasverraes.bsky.social, and Martin Schimak. Thanks a lot for the great work! 2/4