Freelancing

I am an experienced software engineer for all architectures and platforms, from hardware-affine embedded to frontend. I frequently work on roles at senior or team lead level. I also give trainings and workshops. In projects and ventures, I am often refered to as the "universal weapon for any kind of task".

My primary areas of work are big data, platform architectures and working on problems that have been impossible to solve with computers until now. My expertise is a PhD in computational physics and more then 20 years of professional experience in sofware engineering. Over the years, I have taken on various roles, including developer, team lead, architect, analyst, product owner, buisness advisor, founder, chief information officer, supervisory board member and managing director.

Technologies

Handy-on experience in programming ecosystems and environments, sorted by descending preference:

Data science and AI (15 years)

Wolfram Mathematica ‧ CAS/LISP ‧ SageMath ‧ Sage Cell ‧ Reduce ‧ Octave ‧ Julia ‧ Symbolics.jl ‧ ModelingToolkit.jl ‧ JupterHub/JupyterLab ‧ Scipy ‧ scikit-learn ‧ Pandas ‧ Sympy ‧ Anaconda ‧ Bokeh ‧ Altair ‧ Seaborn ‧ R ‧ ggplot ‧ Matlab ‧ Labview ‧ Modelica ‧ Wolfram SystemModeler ‧ Scilab ‧ TensorFlow ‧ PyTorch ‧ Highlight: Engineered world's first open source collaborative notebook interface with the SageMath Notebook in 2012.

Web Programming (+20 years)

HTML5 ‧ XML ‧ XSLT ‧ SVG ‧ CSS/SCSS ‧ PHP ‧ Perl/CGI.pm/mod_perl ‧ Python ‧ Twisted ‧ Tornado ‧ Django ‧ Flask ‧ Sanic ‧ JS/Typescript ‧ Web Assembly ‧ Websocketing ‧ Web periphery ‧ Figma ‧ d3js ‧ Three.js ‧ Vue ‧ Svelte ‧ Sveltekit ‧ React ‧ node.js ‧ deno ‧ Bundlers and Compilers ‧ LAMP ‧ Apache ‧ nginx ‧ SSGs ‧ Highlight: Fullstack frontend and backend before Web 2.0 times

Embedded Systems (10-20 years)

Analog frontends ‧ ARM Cortex ‧ Nordic ‧ STM32 ‧ AtMega ‧ Arduino ‧ PlatformIO ‧ ETL ‧ ESP-ISP ‧ nRF Connect SDK ‧ FreeRTOS ‧ Zephyr ‧ PIO/FlexIO ‧ C/C++ ‧ ARMv6 Assembler ‧ LLVM ‧ GDB ‧ JTAG ‧ lwIP ‧ MQTT ‧ Node Red ‧ Highlight: Real time, networking and data streaming applications in C++

System Programming and Desktop (20 years)

Linux/POSIX ‧ DOS ‧ C/C++ ‧ libc ‧ Shell Scripting ‧ Qt ‧ GTK+ ‧ wxWidgets ‧ X11/Xlib ‧ SDL ‧ Java AWT/Swing ‧ DBus/COBRA ‧ systemd ‧ Highlight: Developed linux kernel modules and userspace tooling

IP Networking (20 years)

Linux Routing and Firewalls ‧ Cisco ‧ Mikrotik RouterOS ‧ OpenWrt ‧ (x)inetd ‧ IPv6 ‧ VLANs ‧ Wireguard ‧ Message Brokers ‧ Protobuf ‧ gRPC ‧ ZMQ ‧ RabbitMQ ‧ Kafka

High Performance Computing (5-10 years)

MPI ‧ OpenMP ‧ OpenCL ‧ SLURM ‧ PBS ‧ Fortran Co-Arrays ‧ domain-specific frameworks ‧ Remote GPUs ‧ VTK ‧ PyVista ‧ Blender/bpy ‧ HDF5 ‧ Ceph ‧ BeeGFS ‧ HPSS ‧ RHEL ‧ Cray ‧ Highlight: Developed Exascale codes running on 300,000 processor cores

Data Bases and Data Warehousing (+5 years)

Dask ‧ Vaex ‧ Apache Arrow ‧ Apache Spark ‧ Apache Airflow ‧ Pentaho ‧ PowerShell ‧ Neo4j ‧ Redis ‧ MongoDB ‧ HBase ‧ InfluxDB ‧ RDF stores ‧ Gephi ‧ Grafana

DocOps and TeamOps (10 years)

MediaWiki ‧ DokuWiki ‧ Outline ‧ Trac ‧ Redmine ‧ OTRS ‧ Zammad ‧ Sphinx ‧ MkDocs ‧ Docsify ‧ Latex ‧ Forges ‧ Gitlab ‧ Github ‧ Gitea ‧ Gogs ‧ SourceHut ‧ Forgejo ‧ Codeberg ‧ Launchpad ‧ Savannah ‧ Atlassian ‧ Highlight: MediaWiki extension and skin developer. Uses Latex in production.

Container and Cloud (5-10 years)

Docker ‧ Docker Copose ‧ Kubernetes ‧ Observation ‧ Jaeger ‧ OpenStack ‧ Vercel ‧ Hetzner/OVH ‧ Golang

Training and Workshops

I love teaching and passing knowledge in a dense and useful form. I used to work in university didactics / higher education paedagogy for 10 years at Goethe University, Frankfurt at stations such as the Interdisciplinary Center for university teaching and learning, Studiumdigitale and my own institution for medialisation and outreach of natural sciences, called PhysikOnline. At Between 2009 and 2019, I raised more then 500kEUR for running teams dedicated to creating content, videos and digital tools. We had several offices and operated own student computer center. Here's a bit of project description.

A few Principles

• I always aim to speak the language of my audience. This principle shapes everything I create — from presentations and documentation to code.
• I view tooling as a social contract. While tools like Kubernetes, NPM, or Golang may not be perfect on their own, their widespread adoption fosters shared context. Effective collaboration often depends on speaking a common technical language.
• I'm a strong advocate for Open Source, including in industrial contexts. My daily tools are primarily open source: LibreOffice, LaTeX, and Linux desktops, among others. I choose them for their portability, accessibility, and scriptability — all of which contribute to efficiency. Still, I'm pragmatic and use closed-source tools when they make sense.
• I value transparency and documentation. My written materials are thorough and complement — rather than duplicate — the available machine-readable formats.
• I don't adopt trends blindly. For instance, my git commits are not always machine-readable, but they leave a meaningful trail for human readers. Similarly, I believe Semantic Versioning often introduces unnecessary complexity by embedding meaning into version numbers.
• The less code, the better. The fewer dependencies, the better. For technical audiences, software can be elegant and expressive. For industry, it often serves as a necessary layer for formalizing collaboration.
• AI has its place in enhancing my effectiveness without compromising data security. I clearly declare when I use it — and yes, even this list was improved with the help of ChatGPT and similar tools through prompts like "improve the formulation"

Roles and clients

I successfully leads heterogenous teams of hardware and software engineers since many years. I also has half a decade of experience in company building and management. My clients range from financial auditing over tech companies to research institutes.

I frequently organize my work via the DenktMit eG but I am also available as self-employed independent freelancer. My Freelancing CV contains a listing of selected projects in various domains and is available on request.