Software Architects
Who want to make decisions under uncertainty and be able to defend them.
Residuality Theory: Barry O’Reilly’s first workshop in Poland
A hands-on, 3-day workshop for architects, tech leads and experienced engineers who design systems in a world of constant change.
Tickets go on sale soon. Join the interest list to hear before anyone else.
Ticket prices · not on sale yet
Join the interest list- Early Birdcoming soonPLN 4,990+ VAT · PLN 6,137.70 incl. VAT6 seats at this price
- StandardPLN 5,990+ VAT · PLN 7,367.70 incl. VAT18 seats at this price
- Late RegistrationPLN 6,490+ VAT · PLN 7,982.70 incl. VAT6 seats at this price
Your system usually fails where you didn’t expect change.
You design a system for the requirements you know today. A year later, regulations, your biggest customer, the business model or the company’s ownership changes. An architecture that made sense starts causing trouble in places that were never on any diagram.
That is exactly the problem Residuality Theory addresses.
In this 3-day workshop with Barry O’Reilly you’ll learn how to design and evaluate architecture not only for what we know today, but also for changes we can’t yet predict.
Who it’s for
Who is this workshop for?
Advanced level. The workshop is for people who design systems and make architecture decisions in their daily work.
Solution Architects
Who design solutions that span many systems, teams and stakeholders.
Tech Leads
Who are stepping into the architect role and need solid foundations.
Senior Software Engineers
Who want to understand why a system has the shape it has, not just how to build it.
Engineering Leaders
Who are leading teams into a major initiative: a new product or a legacy modernisation.
Architecture decision-makers
Who want the whole team to share an understanding of the architecture and a common vocabulary.
You don’t need prior knowledge of Residuality Theory or DDD, or any particular programming language or framework. This workshop is not for people new to system design.
The method
Residuality Theory helps you design systems with change in mind.
It is an approach to architecture design created by Barry O’Reilly. It brings together software engineering and complexity science: the study of systems in which many elements influence one another.
It tackles a problem every architect knows: you have to design the system today, without knowing what changes the future will bring. Instead of guessing, you stress the design against many possible changes and make decisions you can justify.
Key concepts at a glance:
- 01
Stressor
A change in the system’s environment that can destabilise it: a new regulation, a lost customer, a new sales model.
- 02
Residue
What is left of the system and still works after a stressor hits.
- 03
Contagion analysis
Tracing how the impact of a single change ripples across components.
- 04
Incidence and adjacency matrices
Spreadsheet-based tools for deciding where to draw component boundaries.
Trainer
Taught by Barry O’Reilly.
Barry O’Reilly runs the workshop in person. He is the creator of Residuality Theory.
Barry is a software architect and researcher. He created Residuality Theory – an approach that draws on complexity science and philosophy to help teams build systems that survive unexpected change.
- Founder of Black Tulip Technology.
- PhD candidate in complexity science and software engineering at The Open University.
- Has held senior roles at global technology companies, including Chief Architect at Microsoft, where he led the worldwide Solution Architecture community.
- Former startup CTO.
- Has trained architects for years. Runs this workshop for DDD Academy and Avanscoperta, among others.
- Speaker at DDD Europe.
What you’ll take away
After the workshop you’ll be able to:
- spot architectural risks before they turn into expensive problems,
- identify the stressors that affect your system,
- analyse how changes can spread through a system,
- make informed decisions about component boundaries and structure,
- stress-test an architecture against changes nobody can predict today,
- make a stronger case for architecture decisions to both technical and business stakeholders.
Why this workshop
Why spend 3 days on this?
With Barry O’Reilly
The creator of Residuality Theory runs the workshop in person.
Hands-on
This is not three days of slides. Most of the time is spent on hands-on exercises, problem-solving and discussion.
A new way of thinking about architecture
Not another framework or pattern catalogue. You leave with a new way of analysing and justifying design decisions.
Programme · Advanced Software Architecture with Residuality Theory
3 days of working with Residuality Theory.
The programme is exactly the same as in the editions Barry runs abroad.
Foundations
Where system complexity comes from and what Residuality Theory is about.
- Concrete Complexity for Software Engineering
- Philosophy of Architecture
- Representation in Architecture
- Residuality Theory
- Attractor networks
Modelling change
You model stressors and design the architecture of a real system.
- Modelling stress: socio-economic architecture
- Defining residues
- Surviving unknown unknowns
- Producing a real-world architecture
Decisions and testing
You draw component boundaries and test the finished architecture.
- Contagion analysis and component decisions
- Adjacency matrix techniques
- Incidence matrix techniques
- Testing the architecture
Every session combines theory with group exercises, so you apply each technique straight away to a concrete case.
Introduction to the theory
Get started with Residuality Theory
In this talk from NDC Porto 2024, Barry introduces the basics of Residuality Theory. It’s a good starting point before you decide on the workshop.
Watch the talk on YouTubeBooks
Two books by Barry on architecture in uncertain times.
Residues: Time, Change, and Uncertainty in Software Architecture
The foundation of the method. To get the most out of the workshop, read it beforehand.
View on Leanpub
The Architect’s Paradox
Why the architect’s role is so hard, and how to work with that.
View on LeanpubBoth published on Leanpub.
Details
Dates, venue and what to bring.
- Dates
- 1–3 March 2027Monday–Wednesday
- Hours
- 09:30 - 17:00Each day of the workshop (1–3 March)
- Venue
- Warsawexact address coming soon
- Language
- EnglishThe English you use at work is enough.
- Seats
- 30
- Format
- short lectures and hands-on group exercises
- What to bring
- a laptop with a spreadsheet appExcel, Google Sheets or LibreOffice
- Included
- workshop, course materials, lunch and coffee breaks
- Not included
- travel and accommodation
Pricing and sign-up
Ticket sales open soon.
Everyone on the interest list gets early access to tickets. Joining is not a booking and doesn’t commit you to anything.
Early Bird
Launch price. The next price tier applies once these seats sell out.PLN 4,990 + VAT
PLN 6,137.70 incl. 23% VAT · per person6 seats at this price- Next price tiers
- Standard · 18 seatsPLN 5,990 + VAT PLN 7,367.70 incl. VAT
- Late Registration · 6 seatsPLN 6,490 + VAT PLN 7,982.70 incl. VAT
- 3 days of workshop with Barry O’Reilly
- course materials
- lunch and coffee breaks
- VAT invoice
Need to make the case to your employer? Programme, price and terms in one PDF.
Download employer informationFAQ
Frequently asked questions.
Do I need to know DDD?
No. Hands-on experience designing systems is enough.
Do I need to prepare before the workshop?
You don’t have to, but you’ll get the most out of it if you read Barry’s book Residues: Time, Change, and Uncertainty in Software Architecture beforehand.
Is my English good enough?
Yes, if you read technical documentation and work with colleagues in English day to day.
Can I come on my own, without my team?
Yes. Exercises are done in small groups with other participants. Some people come on their own, others with colleagues.
What do I need to bring?
A laptop with a spreadsheet app. Some of the exercises are done in a spreadsheet.
Do you cover accommodation?
The price covers the workshop, materials, lunch and coffee breaks. Travel and accommodation are not included. If you’d like recommendations on where to stay near the venue, get in touch – we’re happy to help.
How do I sign up?
Tickets go on sale soon. Join the interest list and we’ll let you know before anyone else.
Does joining the interest list commit me to anything?
No. It is not a booking or an order. When sales open, you’ll hear from us before anyone else, and it’s up to you whether to buy a ticket.
How does payment work?
Once sales open, you receive a VAT invoice for your ticket. Companies can pay against a pro forma invoice.
When do I have to pay?
Within 7 days of receiving the pro forma invoice. If you buy your ticket after 15 February 2027, you have 3 days. Your seat is confirmed once payment is received. If payment isn’t received on time, the seat is released to the next person.
Can I cancel and get a refund?
Yes, on these terms:
- until 30 January 2027 we refund 100% of the price,
- from 31 January to 14 February 2027 we refund 50% of the price,
- from 15 February 2027 refunds are no longer available, but you can transfer your ticket to someone else.
Send your cancellation to contact@arpeggia.studio. Refunds are issued within 14 days.
What if I can’t attend?
You can transfer your ticket to a colleague free of charge. Let us know at least 3 days before the workshop, with their name and email. If a new invoice is needed, we’ll issue one.
What happens if the workshop is cancelled?
You get a full refund within 14 days. If the workshop is rescheduled, you can keep your ticket for the new date or get a full refund. We can’t cover travel or accommodation costs, so we recommend flexible, refundable bookings.
How is this different from the editions abroad (DDD Academy, Avanscoperta)?
The programme and the trainer are exactly the same. Prices are in Polish złoty (PLN) and you receive a VAT invoice.
1–3 March 2027 · Warsaw
Want to take part?
Tickets go on sale soon. Early Bird: PLN 4,990 + VAT (PLN 6,137.70 incl. VAT).
Join the interest list →