Current focus
COBOL development on enterprise-scale mainframe systems, with attention to structure, reliability, maintainability and the realities of long software lifecycles.
Andy Valkenburg · In@Million
Understanding systems, from Mainframe to AI.
Software engineer, jazz musician and long-time experimenter with technology — from COBOL on large-scale mainframe systems to automation, AI workflows and startup building.
COBOL · z/OS · Zowe · Robot Framework
Jazz bass · systems thinking · Recrugent
Current mode
Complex systems, practical experimentation, product thinking.
In@Million
A personal brand around technology, creativity and building useful things.
About
Curiosity first. Trend second.
I’m a software engineer with one foot in modern stacks and one in long-lived critical systems. By day I work as a COBOL developer at the Belastingdienst, building and maintaining large-scale mainframe systems with z/OS, ISPF, IDz, Zowe and Robot Framework.
In that environment, I’m developing as a technical depth engineer: someone who likes getting below the surface, understanding how things really work, and improving them from that reality rather than from fashion.
Alongside that, I build products and experiments around ideas that keep pulling my attention — recruitment, AI workflows, automation and the space where technical systems start behaving like organizations.
Software engineering
Legacy and modern, both taken seriously.
My technical path combines Java, PHP, Symfony, Laravel, Docker and Scrum/Agile workflows with the realities of enterprise mainframe development.
Broader stack
Experience with mainframe COBOL development, Java, PHP, Symfony, Laravel, Docker and Agile workflows. Comfortable moving between older and newer environments.
Engineering lens
Influenced by ideas from Clean Code, The Pragmatic Programmer and Team Topologies — applied in real systems, not as slogans.
Jazz musician
Listening, timing, interplay.
Alongside software, I’ve kept working as a jazz musician. In projects connected to O.A.P. Records, I appear as a double bassist in recordings such as Solar, Raisin Bread and When We Kiss.
That role is less about standing in front and more about feel, restraint, pocket and interaction. It is a way of thinking that carries into software too: good systems breathe, leave room, and support the whole.
Experimentation timeline
A pattern of exploring early.
AI agents and intelligent systems
Experimenting with AI concepts and agent-like behavior long before the current wave.
Decentralized money
Exploring peer-to-peer digital money as an answer to closed banking systems.
Crypto becomes real
Watching those earlier ideas materialize in the rise of crypto and decentralized systems.
Home Assistant
Designing home automation setups and thinking in sensors, flows, feedback loops and system behavior.
AI-driven organizations
Exploring AI workflows, startup systems and the idea of a zero-human company.
Projects
Things I build around the edges.
AI workflows and agent experiments
Designing flows around content, automation and coordination — not just prompts, but systems that can actually do work.
Home Assistant control logic
Building practical automation with sensors, feedback loops and a bias toward understanding the real behavior of systems.
Recrugent.com
A startup focused on connecting engineers with product-driven teams — based on how teams actually operate, rather than just CV matching.
Visit Recrugent.comHow I work
Complexity is not a reason to back away.
I tend to dive into complexity, figure out what’s really going on, and build on top of that reality.
Whether that means understanding a mainframe workflow, shaping a product idea, wiring up home automation, or turning an abstract concept into a working startup, the common thread is the same: break it down, make it real, improve it.