Niels Castle · Castle+Andersen ApS
Castle+Andersen ApS
Niels Castle
Niels Castle Independent software developer, Hillerød

Designs and builds secure workflow and administrative systems for education, healthcare and logistics, from first conversation to production.

Current focusRust microservices in Docker. Design, deliver and support.

01 · Selected work

Education · since 2013

Rust/FileMaker platform

FileMaker platform in production at a Danish business academy since 2013, now extended with Rust microservices in Docker.

Logistics · Engineering

Route optimization and diagramming

Monolith-to-microservices migration for a UK electrical-testing company and a US school bus planning company. Shortest-path routing with AWS Location Service; PDF diagrams of electrical installations. Node.js to Rust.

Public sector · 2025

esas and an academy merger

Technical lead on the national student administration system at a Danish business academy, member of the Ministry's esas technical advisory board, and technical lead on migrating federated login and integrations through the academy's 2025 merger.

Healthcare · iOS and Android

SimMon

Remote-controlled patient monitor for medical simulation, used by paramedics and training organisations worldwide.

simmon-app.com ↗

02 · Earlier work

  • 112pulsIncident alerts for the Danish Emergency Management Agency
  • PensionsInfoNational pension overview service
  • Fire Hydrant MapLocating the nearest fire hydrant for fire and utility services
  • Term networkSearch technology, C++
  • MRJ PlugInMac OS era

03 · Background

MSc in Computer Science and Communication; BSc in Nursing (RN).

Clinical and emergency services experience shapes how the software is built for people working in the field.