Feedback-Based Development

Roman theatre in St. Albans, GB

Important things need to grow to last. The German says “gut ding will weile haben” – good things take time.

The Roman Theatre of Verulamium (St.Albans) built in about 140AD

I did it: almost exactly four years after Nick Tune suggested me a conference in London as the best place to start talking at conferences, I had my first in-person talk at the DDD Meetup in London. Given the timespan, you could say, “What is so special in this? Why should I continue reading?”. Well, you don’t need to 😀. For me, it feels like quite a wonder that by looking at where I was four years ago (I was completely unknown in the international community) and what happened in the meantime, I can put a ✅behind this bucket list item.

Writing about the last four years would transform this post into a small book – I won’t do that now. Instead, I will tell you a bit about the talk and how I applied the same ideas to prepare for it. The talk is about Feedback-driven Product Development. This post is about Feedback-driven Self-Development😉.

Shifting from Projects to Feedback-Based Product Development
slides on miro

With this talk, I wanted to show how broken our product development processes, long and short-term outcomes, hell, the whole industry is, and they don’t need to be! We have everything we need to improve our life as product developers to enjoy this most creative job, but instead, we feel frustrated, overwhelmed and not fulfilled. In the presentation, I talked about the three things organisations (or single persons) can use to change this.

Disclaimer: I don’t mean software developers here. I mean all the different roles and skills needed to create something good.

Now back to the story I want to tell you: how did I use these three ideas to develop the talk and myself at the same time?

Optimise For the Time to Learn

As I said, I have never written a talk with slides and all. I have even switched from Windows to Linux to never land in a situation where I needed to write a PowerPoint presentation. But the talk itself is only the output, it is not my goal. My goal is to learn if I can do this, if I am good at it. If I enjoy it? I started to speak in international circles on Virtual DDD, and the pandemic made it very easy to meet great people. After three years of interactions, it felt natural to me. We became online friends. Last year I proposed my first workshop at the biggest DDD conference in Europe because I wanted to meet them and knew that I wouldn’t be able to support the trip financially otherwise. It worked, and now I am part of this very special community. It stopped becoming a challenge; I needed something new: a talk presented on a podium, completely out of my comfort zone.

You need to know that I am not a consultant (and I still don’t want to become one), so there are not too many reasons for all the effort needed to travel abroad to conferences and give a high-quality workshop or talk. One (and still the main reason) is to meet and exchange with other nerds. The other is my personal development: can I do this? Where are my boundaries?

So that in January, Nick convinced me to dare the next step. We agreed on a date and on a (vague) topic and set the first milestone with this: learn. Learn about the fun, the (lack) of skills in presenting my thoughts, and the reaction of others. If they are interested at all in what I want to say. My slides (the output) needed to be good enough (on my own quality scale) so that I could achieve these goals.

Measure the Outcome

The outcome was great! Even if it was a complicated plan, everything worked out, and I was ready to go. This meetup, in a city where almost no one knew me (so that they were unbiased), with a topic which could have been everything or nothing, the splendid location at Mastercard providing the conference feeling – all this was on purpose to get the most honest feedback. After seeing several people nicking during the talk, making multiple connections on LinkedIn and mastodon directly after the session, and getting several “Thank you for addressing this” comments, I could tick one important question: people want to know what I am speaking about ✅

The question about joy, about having fun, was answered too: yes, I had fun. I had great conversations with myself while I was writing the talk, and I had better conversations with the people in the room ✅.

Embrace the Change

The best outcome I learned by giving this talk was that it is not good enough yet. Imagine the other situation: having it perfect for the first time. Where am I going from here? What a boring (hence scary) thought! After this first practice, I now know (and not guess) that I will need to rework everything, but my first “walking skeleton” is the right one; the first step was exactly in the right direction. The next iterations can come.

The next milestone is at the beginning of October at KanDDDinsky. The steps towards it will be small and several based on feedback from Nick, Andrea, or anyone up to it. My journey to find my boundaries can continue.

(Data) Ownership, Boundaries, Contexts – what do these words mean?

In the last months, we started to use these terms more and more at my company without discussing the concepts behind them. One day I was asked, “What do you mean by data ownership?” 🤔 The question made me realise that I don’t know how much of these concepts are understood.

These terms refer to sociotechnical concepts (some originating from Domain-driven design). They refer to one possible answer to the question: how can a product be improved and maintained in the long term? How can we avoid hunting for weeks for bugs, understanding what the code does, finding out what it should do, and hoping that fixing one issue does not lead to a new problem? How can we continue having fun instead of becoming more and more frustrated?

Real digital products address needs which were fulfilled earlier manually. Companies which survived the first years of testing the product are often innovators in their market. They have chances to stay ahead of the others, but they have the burden of solving all questions themselves. I don’t mean the technical questions; nowadays, we have a considerable toolbox we can use. But all the competitors have that toolbox too. The questions to answer are how to organise in teams and how to organise the software to reach a steady pace without creating an over-complicated, over-engineered or over-simplified solution.

How to get a grip on the increasing complexity built up in those years when the only KPI that mattered was TTM (Time-to-Market)?

Years ago, the companies creating software to help automate work answered this question with silos around the architecture: frontend, backend, processing, etc. In the meantime, it became clear that this was not good enough.

Engineers are not hired to type code but to advise and help to solve problems. 

This means they should not belong to an engineering department anymore but be part of teams around different topics to handle: marketing, search, checkout, you name it. These are sub-domains or bounded contexts (depending on the importance of the subject, more than one bounded context can build the solution for the same sub-domain). These contexts and their boundaries are not fixed forever because the context changes, the market around the company changes, and the needs change. The people involved change and, finally, the effort needed changes. The best way also to define them is to take a look at how the business is organised (sales, marketing, finance, platform, developer experience, etc.) and how the companies using the product are organised (client setup, client onboarding, employee onboarding, payroll period, connected services, etc.). By aligning the software and – to get the most significant benefit – the teams to these sub-domains, you can ensure that the cognitive load for each team is smaller than the sum of all.

What are the benefits?

  • The domain experts and the engineers speak the same language, the ubiquitous language of their bounded context, to use the DDD terms.
  • The teams can become experts in their sub-domain to make innovation and progress easier as the problems are uncovered one after another. They can and will become responsible and accountable about their domain because they are the only ones enabled to do so.
  • Each team knows who to contact and with whom to collaborate because the ownership and the boundaries are clear. (No long-running meetings and RFCs anymore by hoping to have reached everyone involved).

What does data ownership mean in this case? Data ownership is not only about which team is the only one controlling how data is created and changed but also the one controlling which data is shared and which remains implementation detail. This way, they stay empowered and autonomous: they can decide about their experiments, reworks, and changes inside their boundaries.

Data ownership also means process ownership. 

It means the team which owns the data around “expenses”, for example, owns the features around this topic, what is implemented and when so that they are involved in each improvement or change regarding expenses from the beginning. This is the only way to respect the boundaries, take responsibility, and be accountable for all decisions around the software the engineers create.

Applying these concepts can’t be done overnight, mainly because it is not only about finding the (currently) good boundaries but also shifting the mindset from “let me build something” towards “I feel responsible for this part of my product”. It needs knowledge about the product and a lot of coaching and care. But finding the boundaries to start with should be doable in case of a product already established on the market and with a clear strategy. The alternatives are silos, continuously increasing cognitive load or the loss of an overview and local optimisations.

KanDDDinsky 2022 Watch-List

This is the list of the sessions I watched, some with additional insights, others as a resource. All of them are recommended if the topic is interesting to you.

All sessions recorded during the conference can be viewed on the KanDDDinsky YouTube channel.

Keynote By Mathias Verraes about Design & Reality

Thought-provoking, like all talks I saw from Mathias.

Connascence: beyond Coupling and Cohesion (Marco Consolaro)

An interesting old concept regarding cohesion and good developer practices. Fun fact: I had never heard of Connascence before, but two times at this conference 😀.

Learn more about this from Jim Weirich’s “Grand Unified Theory of Software Design” (YouTube). It is a clear recommendation for programmers wanting to learn how to reduce cohesion.

Architect(ure) as Enabler of Organization’s Flow of Change (Eduardo da Silva)

The evolution of the rate of change in time

“The level and speed of innovation has exploded, but we still have old mental models when it comes to organisations” – Taylorism says hello 🙁

Evolution pattern depends on architectural and team maturity.

“There is no absolute wrong or right in the organisational model of the architecture owners; it is contextual and depends on the maturity.”

This talk is highly recommended if you work in or with big organisations.

Systems Thinking by combining Team Topologies with Context Maps (Michael Plöd)

A lot of overlapping between Team Topologies and DDD

💯 recommended! (The slides are on speakerdeck.)

Road-movie architectures – simplifying our IT landscapes (Uwe Friedrichsen)

There will always be multiple architectures.

“The architecture is designed for 80-20% of the teams, and it is ignored by 80-20% of them.”

The complexity trap

Uwe describes his concept-in-evolution of a desirable solution that could help avoid the different traps. They should be

  • collaborative and inclusive,
  • allowing to travel light with the architecture,
  • topical and flexible

The concept is fascinating, with a lot of good heuristics. A clear recommendation 👍

How to relate your OKRs to your technical real-estate (Marijn Huizenveld)

Common causes of failure with OKRs
Combine OKRs with Wardley Maps

The slides are on speakerdeck. Marijn is a great speaker; the talk is recommended if you work with OKRs.

Improving Your Model by Understanding the Persona Behind the User (Zsofia Herendi)

Salesforce study: 76% of customers expect companies to understand their needs and expectations.

😱 what about the rest of 24%?!! Do they not even expect to get what they need?

Zsofia gives a lot of good tips about visualising and understanding the personas.

Balancing Coupling in Software Design (Vladik Khononov)

Maths meet physics meet software development – yet again, a talk from Vladik, which must be seen more than once.

The function for calculating the pain due to cohesion.

By reducing one of these elements (strength, volatility, distance) to 0, the maintenance pain due to coupling can be reduced to (almost) 0. Now we know what we have to do 😁.

Culture – The Ultimate Context (Avraham Poupko)

Why does not have the DDD community any actual conflicts? Because our underlying concept is to collaborate – to discuss, challenge, decide, agree, commit (even if we disagree) and act.


This talk is so “beautiful” (I know, it is a curious thing to say), so overwhelming (because of this extraordinary speaker 💚), it would be a failure even to try to describe it! It is available, go and watch it if you want to understand the DDD community.

This list is just a list. It won’t give you any hints about the hallway conversations which happen everywhere, about the feeling of “coming home to meet friends!” which I got each year, and I won’t even try 🙂.