About
One engineer, and everything under it
Xerdi is Erik Nijenhuis, working from Leeuwarden in the north of the Netherlands. Small on purpose: the person who scopes the work is the person who builds it.
Digital autonomy, and why it is on the invoice
Xerdi runs its own git, its own identity management, its own mail, its own TeX distribution mirror. Not as a hobby, and not as a cost centre — as the evidence for the thing we sell. It is difficult to credibly build systems that someone else can own and operate if you have never operated your own.
The practical consequence for a client is a short list. Everything is free software, so there is no licence that can be withdrawn. Everything is deployed from source under version control, so a server can be rebuilt rather than nursed. And the handover is real: the sources, the deployment and the documentation, not a login to something we host.
Standards work
Part of this work happens in public. Xerdi contributes to the TeX ecosystem, publishes packages, and takes part in the ongoing work on accessible and archivable PDF — tagging in particular, where the gap between what a file claims and what it delivers is still wide.
Six of those packages are on CTAN, where the source and the documentation can be read without asking us for anything. Erik has sat on the board of the TeX Users Group since 2025, and serves as its vice president. Both are published by those organisations rather than only here, which is the point of mentioning them at all.
That participation is also why our own conformance claims are conservative. A file here declares PDF/UA-2 only where a real structure tree backs it up. Declaring accessibility a document does not provide is worse for the person relying on it than declaring nothing.
The packages on CTAN The TUG board PDF accessibility at TUG The LaTeX Project
Where this sits
Xerdi is a Red Hat partner, and Erik is an associate member of the Free Software Foundation. Those two sit together more comfortably than they might sound: the second is why everything we ship is free software, and the first is how that lands in an organisation that needs a supported platform underneath it and a support contract someone can point at.
Neither is an endorsement of Xerdi by anyone. They are stated because they say something about what we build on and where we stand, and because a client is entitled to check both.
The rest of Xerdi
xerdi.nl
Websites and business e-mail for Dutch organisations. In Dutch.
xerdi.frl
Linux workplaces and computer help in Friesland, in person. In Frisian.
maclotsen.com
The person behind all of this. Erik's own site carries the published papers, the packages and the talks, with a record of what he has worked on and for whom — worth a look if you are weighing up a small supplier.
Questions before a project
Technical questions are welcome without a project attached. If we can answer it in an e-mail, we will.