About
Six domains. One specialist. Direct contact.
stuf.rocks is the service brand of ndtss/Stefan Köllner — based in Hamburg, with over 30 years of software engineering across web, desktop applications, embedded data acquisition, mobile app development, Linux server operations and AI-assisted tooling. The shop offers concrete, scope-bound engagements; larger custom work runs via direct coordination.
What's delivered here is not generic agency output — it's code from a specialist who chooses the stack, writes the code, operates the servers, and answers the emails. Architecture principles (loose coupling, testability, extensibility) are non-negotiable: the result is software you can still change two years from now.
Also behind ndtss — NDT Software Solutions, with products in use across Europe and the GCC. Over a decade of hands-on Linux server operations rounds out the toolbox.
Principles
How the work is done.
Modules know each other through interfaces, not concrete classes. Layers are respected — no shortcuts that come back in year two. No quick'n'dirty but fast-and-reliable — everything fully documented.
Pure functions where possible, side effects isolated, dependency injection over hidden singletons. Tests are how the code stays alive.
New sources, new views, new filters arrive as extensions, not by patching existing code. Open/Closed in practice.
Logs, metrics, restore-tested backups, runbooks. Software that ships is software that runs — and gets observed when it does not.
Methodology
How delivery happens.
Short iterations, early feedback loops, shippable increments instead of big-bang releases. Direction can adjust without throwing away work.
Working prototypes in days, not weeks. Iterative refinement with the customer — assumptions are validated against running software, not slide decks.
Deliberate user journeys, clear information architecture. Focus on polished, learnable interaction rather than feature sprawl. Mature, intuitive UI/UX: the UI learns from the user — not the other way around.