Mark de Jong

Writes robust and scalable software, designs user-friendly interfaces, asks the right questions, mentors others, and reviews code with care. I work under the name Vectos—Spanish for vector, meaning magnitude and direction—because I value both clarity and purpose in what I build.

With over 13 years of professional experience, I’ve delivered projects across diverse industries including renewable energy, logistics, finance, healthcare, telecom, and education. From building high-performance backends and large-scale billing systems, to crafting custom CMS platforms and mobile apps, my work combines functional programming principles with real-world impact.

I’ve contributed to open-source projects like Cats, Tapir, and Doobie, and introduced novel ideas such as the Saga Monad (now adopted in Arrow and ZIO). I'm driven by curiosity, and I enjoy solving hard problems—whether it’s optimizing protocols, designing internal DSLs, or writing firmware in Rust for embedded devices.

In my professional career I have worked at various companies doing diverse projects.

  • Development of custom content management systems
  • Development and moderation of community websites
  • Improving performance of existing software
  • High performance backends
  • Financial systems
  • Marketing pages
  • Single page web apps and mobile apps.
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Mark