Gijs Nijholt - Solo Developer & UI Engineer

Hydrodynamic simulation is a complex process.

One of the more surprising things I built during the Rana HTMX rewrite was collaborative cursor presence.

One of the first things I wanted to do while working on the HTMX rewrite was search.

This HTMX rewrite is part of Rana’s internal engineering/UX exploration.

The Rana QGIS plugin didn’t run on macOS.

The software behind Rana’s hydrodynamic solver (internally called RanaHCC, the Hydrodynamic Computational Core) is a serious piece of engineering: a Fortran finite-volume solver on a quadtree grid, with Python bindings generated by f90wrap, wrapped in a c…

As part of our UX discovery process, I’ve built a spike to find out what is possible regarding a built-in AI assistant.

The current Rana Water Intelligence website does its job, but I think there’s room for improvement.

Hydrological models like Rana (formerly 3Di) need land use maps.

I built a demo that runs QGIS compiled to WebAssembly in the browser, exposes GEOS to JavaScript, and adds multiplayer editing on top.

We built a Claude skill for the HCC API, and the first time I used it in a real conversation I got back a list of 42,815 simulations.

One of our users filed a bug report with a screenshot attached: the map scale bar had disappeared.

After the morning empathy mapping session we had energy left, so we stayed in the room and did a quick design sprint on one of the ideas that had surfaced repeatedly: automatic water storage management.

We ran a spike to find out whether we could build a usable schematisation editor inside Rana — in the browser, without QGIS.