Sebastiaan den Boer - Projects

Insufficient Data

2026-03-31T00:00:00+00:00

A technical blog where I document infrastructure work, debugging stories, and lessons learned from building and maintaining self-hosted systems.

The blog itself is built with Zola — a fast static site generator written in Rust — and served through the denboer.cloud infrastructure. Content is written in Markdown, version-controlled in Git, and deployed automatically on push.

Writing here serves two purposes: it forces me to think clearly about what I've built, and it creates documentation that might help someone else facing the same problem.

Digital Portfolio

2026-03-26T00:00:00+00:00

This site — my personal identity and portfolio — built with Zola (a fast static site generator written in Rust) and deployed through self-hosted infrastructure.

Design principles:

No JavaScript — all interactivity through CSS transitions and :hover</code>/:focus-visible</code> states</li>
No external resources — fonts self-hosted, no CDNs, no analytics, no tracking</li>
Semantic HTML — accessible, screen-reader-friendly markup</li>
Single CSS file — organized with @layer</code> for explicit cascade control</li> </ul> Deployed automatically via GitHub Actions and served by Caddy.



Mendix Test Automation with Robot Framework
2023-02-01T00:00:00+00:00
A demo solution — originally built for a Mendix Meetup presentation — showcasing how to use Robot Framework combined with Playwright for UI test automation in Mendix applications. This project bridges the gap between low-code development and professional test automation practices.</p>
The "Solar System Explorer" is a fictional Mendix application used to demonstrate:</p>

End-to-end UI testing</strong> of Mendix applications using Robot Framework</li>
Playwright integration</strong> for reliable, modern browser automation</li>
Reusable test patterns</strong> that can be adopted in any Mendix project</li>
CI-friendly setup</strong> for integrating automated tests into deployment pipelines</li>
</ul>
This work ties into my broader focus on DevOps and test automation in the Mendix ecosystem, which I also pursued during my time as Quality Assurance Engineer and Principal IT Architect at CGI.</p>


Pathfinder
2018-08-01T00:00:00+00:00
Pathfinder is the custom-built CRM/ERP system powering the day-to-day operations of Space Society Twente</a>. Built with Python and Django CMS, it serves as the central platform for managing the association's members, events, and finances.</p>
Core functionality includes member registration and profile management, event creation with attendee tracking, and integrated online payments through Mollie. Background task processing is handled by Celery with RabbitMQ as the message broker, used for sending transactional emails, processing payment webhooks, and other asynchronous workloads.</p>
The project also includes a Discord chatbot that automates role assignments for verified members, granting access to relevant channels based on their membership status, as well as project and committee involvement.</p>
On the infrastructure side, Pathfinder runs on a self-managed Linux server with Nginx as the reverse proxy, handling SSL termination, static file serving, and upstream routing to the Django application.</p>


Space Society Twente
2018-08-01T00:00:00+00:00
I co-founded Space Society Twente in 2018 as Twente's first space-focused student association, creating a platform where students, researchers, and space industry representatives collaborate on aerospace projects — including CubeSat development and a rocket programme.</p>
As President (2018–2019) and NASA Space Apps Local Lead (2018–2020), I organized the Dutch editions of NASA's International Space Apps Challenge, managed fundraising and stakeholder relations, and grew the organisation to 100 members and 17 partner organisations in two years.</p>
As Lead Backend Developer (2018–present), I built and maintain Pathfinder</a> — the association's custom-built CRM/ERP system for its day-to-day operations.</p>


Vindo
2018-05-01T00:00:00+00:00
Vindo was built during ActInSpace 2018 — a mobile application that helps people relocating find a city that suits them best. By leveraging Copernicus Earth Observation data, the app provides location-based insights and recommendations, allowing users to evaluate cities against their lifestyle and environmental criteria.</p>
The application encourages cities to adapt to citizens' needs, fostering a match between people and places based on real satellite-derived data about air quality, green spaces, climate and other environmental factors.</p>
Vindo won the FabSpace 2.0 Prize</a> at ActInSpace 2018</a>, presented by Aerospace Valley and the Paul Sabatier University at the Toulouse Space Show. The prize included a trip to Toulouse for the international finals, expert mentoring, and a meeting with an Airbus representative.</p>


UberWasser
2017-04-01T00:00:00+00:00
UberWasser was built during the NASA Space Apps Challenge in April 2017 — a mobile application that consolidates beach hazard information into a single platform, helping beachgoers monitor risks and take protective measures.</p>
Going to the beach is dangerous: skin cancer and drowning are common risks due to insufficient accessible information. UberWasser addresses this by integrating Sentinel/Copernicus satellite data, open-source mapping and in-situ measurements to deliver accurate information on water quality, UV exposure, sun protection and beach facilities — increasing safety in and out of the water.</p>
UberWasser achieved Global Nominee status at the 2017 Space Apps Challenge.</p>


Space Buddies: The Moon
2016-04-01T00:00:00+00:00
Space Buddies: The Moon was built during a hackathon in April 2016 — an interactive app for children (6–14) that uses smartphone sensors to locate the moon. The goal is edutainment and raising awareness about lunar missions around the world.</p>
After launching the app, the child is asked to find the moon, aim for it and perform experiments to experience and learn about the moon through the eyes of either an astronaut, a rover or a satellite.</p>
The application features a self-guided learning method with the assistance of a virtual presence (Space Buddy), which assists the player where needed, evaluates outcomes and results of actions taken by the player and provides more in-depth information when appropriate. All communication uses easy-to-understand English.</p>
The difficulty level of certain aspects is scaled based on the amount of space-related knowledge the player has shown to understand.</p>


Euthenia
2015-04-01T00:00:00+00:00
Euthenia was built during the NASA Space Apps Challenge in April 2015 — an interactive web application to visualize global and local food security by analyzing domestic food production, consumption, and international trading patterns.</p>
Food security is one of the most pressing global challenges: one in nine persons suffered from chronic undernourishment during 2012–2014, and the world population is projected to reach 9.6 billion by 2050. Addressing food supply challenges requires collective action spanning land use policy, agricultural practices, consumption patterns, and trading strategies.</p>
Euthenia provides data visualization tools that reveal insights about how countries produce and trade food resources, helping users understand patterns that could inform policy and strategic decisions.</p>


MetroTour
2012-05-01T00:00:00+00:00
MetroTour was a mobile application providing real-time sports updates on the Tour de France to over 10.000 users across 25 international markets. Built with C#/.NET for the Universal Windows Platform during my high school years (2012–2015).</p>
The app was highlighted in the Windows Phone Marketplace for approximately two weeks and received promotional support from both Microsoft and Nokia — a formative experience that sparked my career in software development.</p>