A manager who has been accountable for business-critical software — in a family-owned company and in a corporate group — and takes that accountability on again for a fixed term: as Chief Product Owner, Head of Engineering or Enterprise Architect. I do the building myself.
I build things myself, which is why I know when a concept breaks against the reality of delivery.
Leon Köllerwirth
Selected companies and engagements
Former employers and engagements, not presented as current partnerships or client relationships.
Two services, one way in: a 20-minute introductory call. That is where it becomes clear which form holds — accountability for a fixed term, or a venture that gets built and handed over.
Accountability for a fixed term: as Chief Product Owner, Head of Engineering or Enterprise Architect. Roadmap, releases and architecture, with the teams that carry them — until the position is filled again or the venture is on its feet.
View the offeringBusiness-critical platforms from the decision through to operations: what gets built, how it is cut, and what has to be evidenced before anyone signs the release.
View the offeringHow I lead: 21 rules you can hold me to. Each one names its trap.
Two routes, and both begin with the same 20-minute call. Where the role is clear, it leads straight into a mandate: interim leadership, with the accountability that comes with it. Where it is still open what should be built or released, an assessment in ten working days comes first.
The worked-out format
In 10 working days, from a real product or workflow question to a go/no-go basis for deciding. One prioritised venture, a clear scope, a fixed price.
10 working days · fixed price from €8,500 net
See the offering in detailHow we work
First the business problem, then the decision about what gets built at all. Architecture, organisation and approval follow. The order holds, because each step is what makes the next one possible.
What gets built is decided before the first line of code: make-or-buy, scope and priorities. After that it ships rather than being designed further.
Target states, platform boundaries and dependencies connect strategy with a system landscape that holds.
Roles, teams, portfolio decisions and adoption turn architecture into an organisation that can work.
Decision rights, risk, data and accountability are settled before a solution scales.
razbiram.com is the largest piece of work of my own: a complete learning platform, built by me and in operation on the web. Alongside it, StudyWithMe, a platform in development. Technical detail lives on the product page.
A complete learning platform on its own foundation, live on the web: for Bulgarian, for English-speaking medical students and other learners. The native iOS app is in preparation. Shows agentic content pipelines, evaluation against golden sets and live operation.
View liveAn institutional, curriculum-grounded learning platform in development: personalised learning paths, source provenance, knowledge linking, traceable didactic reasoning. A platform case, not a finished client reference.
FAQ
Engagements across Europe, in German and English, hybrid or remote.
contact@leon-koellerwirth.comWithin 10 working days: two executive interviews, the analysis of one prioritised critical workflow, an opportunity and friction model, an economic hypothesis as a value-effort frame, a Pilot Decision Frame, and a decision document of 10–15 pages. Regulatory questions are named, not legally assessed. Not included: revision loops, further interviews, additional workflows, architecture deep-dives and implementation — all available as change requests. Fixed price from €8,500 net, half on engagement, half on delivery.
Both. The last mandate was the operational case: four years as Interim Chief Product Owner at an inverter manufacturer — product management, engineering organisation and system architecture across several teams, with roadmap, backlog, releases and priorities. Not an advisory position. Which form fits — interim leadership, a mandate or advisory — is settled in the introductory call.
Structures that keep working without me. In the last mandate, at an inverter manufacturer, those were a company-wide architecture platform with architecture principles, decision processes and governance, SAFe anchored in the organisation rather than merely taught, domain teams, and end-to-end processes for portfolio, architecture and development. In the assessment it is the decision document, which stays in the company and can be argued with in my absence. A mandate that only works while the external person is present has missed its purpose.
A fractional CTO leads on an ongoing basis, a few days a week. That is right when a position has to be permanently staffed. Here there are two routes. Where the role is clear, it is interim leadership: the position for a fixed term, with the accountability that comes with it, and nothing before it. Where it is still open what should be built or released, a bounded assessment comes first, with a fixed price, a fixed duration and a document that stays in the company. The difference is not availability. Role and decision are two different questions.
Next step
A confidential conversation clarifies whether the business problem, accountability frame and execution path fit together. That holds for engagements and advisory as much as for interim responsibility and permanent leadership roles. Which form of collaboration fits is something we clarify there.
At the start, everything at once.
Then one thing falls into the next, until the unrest finds a beat.
Not a standstill. Just a form that has learned to carry itself.