--- title: Dennis Krul description: Dennis Krul — Tinkerer and Linux nerd url: https://www.krul.nu/ --- ![Photo of Dennis Krul](https://www.krul.nu/img/dennis.png?v=20d04beb) Tinkerer and Linux nerd # Hi, I'm Dennis Krul I've worked with Linux and the web since the nineties, and these days I lead operations at a hosting company. I live in Delft, the Netherlands, with my wife and three kids, and at home I tinker and self-host. [Connect on LinkedIn](https://www.linkedin.com/in/dennis-krul-8737b1) ## Work As director of operations I'm responsible for the teams and the roadmap behind our servers, storage, virtualization, networking and datacenters. I've been a Linux/UNIX systems engineer, a [PHP](https://en.wikipedia.org/wiki/PHP) web developer, a founder, product owner, team lead and architect, so I know the work from the inside, and I still like to understand how things run before deciding how they should. I engineer software, but I wouldn't call myself a software engineer: I build things to make computers do what I want. ## Tinkering My job is no longer hands-on, so I tinker at home and try to keep up with new tech. My main project is EMS, which manages the energy in our house and replaced [Home Assistant](https://www.home-assistant.io/); more on the EMS page, its electricity prices under Energy. My desktops and servers run [Debian](https://www.debian.org/). ## Going electric Our house is fully electric: 30 solar panels on a 7.4 kW inverter, an [air-source heat pump](https://en.wikipedia.org/wiki/Air_source_heat_pump), induction cooking, the home battery and an [IONIQ 5](https://en.wikipedia.org/wiki/Hyundai_Ioniq_5). The gas connection is gone, which saves its fixed charges too. I did it for the climate, for the cost, to depend less on gas, and because it's a fun system to build and tune. I haven't found a downside: it's cheaper than before, the heat pump keeps the house at an even temperature, and road trips across Europe never had me worried about range. ## AI I use AI a lot, to build my own software and run my infrastructure: this site, EMS and the price API behind the Energy page were made that way. I don't call it [vibe coding](https://en.wikipedia.org/wiki/Vibe_coding) but co-development: I'm the architect and analyst, with the experience of what makes software good, and AI agents are my coders, testers and advisors. It does worry me that I'm coming to depend on a few frontier models, a new big-tech dependency in the making. [Open-weight models](https://en.wikipedia.org/wiki/Open-source_artificial_intelligence) are nearly good enough, but running them at home is still impractical; I hope that changes in the coming years. ## Digital independence I'd rather fix my own things, own my data and keep it private than depend on someone else, and I look for the free alternative first, [free as in freedom](https://en.wikipedia.org/wiki/Free_software). Working in hosting, I'd also like Europe to depend less on the handful of American companies that run much of the internet. So I self-host: [OpenCloud](https://opencloud.eu/en) for files, [Immich](https://immich.app/) for photos, [Forgejo](https://forgejo.org/) for code and [CI/CD](https://en.wikipedia.org/wiki/CI/CD), on a [Proxmox](https://www.proxmox.com/en/products/proxmox-virtual-environment/overview) server at home and [VPSes](https://en.wikipedia.org/wiki/Virtual_private_server) and backups at EU-owned hosting companies. I left Facebook and X and kept LinkedIn for work; this site is my place on the web instead, with nobody's algorithm in between. I'm not dogmatic: my mail is with [Fastmail](https://en.wikipedia.org/wiki/Fastmail), and I use a smartphone, streaming services, AI tools and, for work, Microsoft and the big clouds. I just like to know what I depend on, and to keep a way out. ## How I got here - **1979** Born: version 1.0 released, no manual included. - **1990** First lines of code written, in [GW-BASIC](https://en.wikipedia.org/wiki/GW-BASIC) on MS-DOS. - **1994** Running a [BBS](https://en.wikipedia.org/wiki/Bulletin_board_system) on [FrontDoor](https://en.wikipedia.org/wiki/FrontDoor) and [RemoteAccess](https://en.wikipedia.org/wiki/RemoteAccess). - **1995** First Linux install: [Slackware](https://en.wikipedia.org/wiki/Slackware), on a 386. - **1997** An always-on cable modem, and a Linux box as my home network's gateway and its web and FTP server. - **1999** Discovered PHP 3: Linux and the web have been my thing ever since. - **2001** Along the way: [Solaris](https://en.wikipedia.org/wiki/Oracle_Solaris), [HP-UX](https://en.wikipedia.org/wiki/HP-UX), [AIX](https://en.wikipedia.org/wiki/IBM_AIX) and [Tru64](https://en.wikipedia.org/wiki/Tru64_UNIX), and [Linux on IBM mainframes](https://en.wikipedia.org/wiki/Linux_on_IBM_Z). - **2008** Started a VPS company with two partners, on a platform we built ourselves, fully self-service and automated. Initially on [Xen](https://en.wikipedia.org/wiki/Xen), later migrated to [KVM](https://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine). Open to customers from 2009. - **2018** Sold my shares. Then product owner, Linux team lead and IT architect. - **2026 – Now** Director of operations at a hosting company. ## [EMS](https://www.krul.nu/ems.md) **Energy management** The system I built to manage every energy flow in my house, and what it saves. ## [Energy](https://www.krul.nu/energy.md) **Energy prices** Dutch dynamic electricity prices per quarter hour, and the cheapest supplier for you.