Building Software That Just Works
Jacek
Galowicz
Founder & Director · Applicative Systems Group
I lead Applicative Systems Group, where we build high-assurance NixOS for embedded and cloud-native systems. We also teach it: to teams at Nixcademy, and to individual engineers at the Institute of Nix. With deep expertise in C++, Haskell, Nix/NixOS, and systems architecture, I help teams build software that stays reliable as it scales.
🇩🇪 Deutsch🇬🇧 English
Organizations
What I Lead
Applicative Systems Group
High-Assurance NixOS for Embedded & Cloud-Native SystemsConsulting through corporations in the United States and the European Union: reproducible device images with signed OTA updates, hardened build-to-deploy supply chains, and hermetic CI.
Nixcademy
Instructor-Led Team TrainingOn-site and online Nix & NixOS training with custom syllabi. 1000+ developers trained.
Institute of Nix
Self-Paced CoursesLearn Nix & NixOS the practitioner's way, with video courses like Nix 101 and the book Nix Anti-Patterns.
Public Speaking
Talks & Interviews
Conference Talks
Interviews & Podcasts
Writing & Teaching
Publications
Nix Anti-Patterns
A practical guide to scaling deployments and avoiding common pitfalls.
C++17 STL Cookbook
Recipes for the C++ STL covering algorithms, containers, iterators, and modern C++.
C++17 in Detail
By Bartlomiej Filipek. A comprehensive guide to all the major features introduced in the C++17 standard.
heise online & c't Magazin print · Articles
Academic Papers
- Bit-for-Bit: How We Built a Sovereign, Reproducible Container Supply Chain for DevGuard Technical Report · DevGuard, 2026
- Combining Mechanized Proofs and Model-Based Testing in the Formal Analysis of a Hypervisor FM 2016: Formal Methods
- Efficient Implementation of the bare-metal Hypervisor MetalSVM for the SCC MARC 2012 Symposium
Cyberus Technology · CPU Vulnerability Research
Engineering Philosophy
How I Build Software
Shift Errors Left
Catch problems at compile time, not in production. Strong type systems, exhaustive pattern matching, and static analysis eliminate entire categories of bugs before code ever runs.
Control Complexity
The hardest part of software is managing complexity. I design systems with clear boundaries, minimal surface area, and composable abstractions that remain understandable as they grow.
Automate Confidence
Reproducible builds, automated testing, and continuous deployment pipelines that give teams the confidence to ship changes without fear. Infrastructure defined as code, verified by machines.
Software That Lasts
I build systems that continue working — through team changes, scaling demands, and years of maintenance. Good architecture pays dividends long after the initial delivery.
NixOS 
C++ 
Haskell 
PostgreSQL 
Qt 
PureScript 
Python 
React Tech Stack
Architecture & Development
Most of my experience focuses on embedded (x86-64 and ARM) and backend development on Linux with C++ and Haskell. I use strong type systems to define error states out of existence wherever possible.
In frontend development, I have the most experience with the Qt Framework on Linux and Windows. I've also built rich web and desktop applications against REST APIs with React, typically with the type safety of PureScript.
I am the maintainer of the Python NixOS Integration Test Driver in the nixos/nixpkgs project on GitHub.
Experience
Work Background
Founder & Director @ Applicative Systems Group
Consulting group with corporations in the United States and the European Union, helping organizations deliver higher software quality faster.
- High-assurance Linux and NixOS infrastructure for embedded and cloud-native systems
- Reproducible builds, hardened software supply chains, and CI/CD automation
- Architecture reviews, hands-on development, and long-term technical mentoring
- Nix & NixOS training for 1000+ developers through Nixcademy and the Institute of Nix
Visiting Lecturer @ FH Münster
Held the lecture "Quality-Assuring Software Engineering Methods" for master students — unit & integration testing, spec-driven testing, fuzzing, reproducibility, and established anti-patterns.
Co-Founder & Partner @ Cyberus Technology GmbH
- Automation/integration of software modules into system images (C++, CMake, Meson, GitLab, Docker, Nix)
- Design of Hardware-In-the-Loop (HIL) test infrastructure (Haskell, Python, REST, NixOS, Raspberry Pi)
- Implementation of low-level libraries for embedded systems (C++, Template Metaprogramming)
Sr. Software Engineer @ FireEye, Inc.
- Secure, microkernel-based virtualization platform (C++14, C, Assembler, ACPI, Intel VT, PCI, Qt)
- Automated hardware test infrastructure design and implementation
Student Intern / Master Thesis @ Intel Corporation
- Live migration for a VM monitor based on NOVA Microhypervisor (lwIP TCP/IP, Intel VT)
- ACPI, PCI hot-plugging, TCP connection preservation, network trunking
Student Assistant @ RWTH Aachen University
- Low-level kernel programming, hypervisor development
- Benchmarks and GUI frontends (C/C++, OpenMP, MPI, Qt)
Freelancer @ Academy GmbH & Co. KG
Framework design for web-based medical decision support systems, GUI frontends (Qt, JavaScript).
Academic Background
Education
Live Migration of Virtual Machines between Heterogeneous Host Systems — PDF
Design and Implementation of a Virtualization Layer for the Operating System Kernel "MetalSVM" — PDF
Special thanks to Brunel, E-Plus, and Intel Corporation for co-financing my education through the Germany Scholarship.