About

Mark de Jong is an experienced software engineer, which writes robust and scalable software, designs user-friendly interfaces, very critical, mentors others, and reviews code with care.

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 Scala projects mostly 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.

Next to all of this in my personal life I like to sport, travel and learn about new things

Mark

Tech volunteer

During the years I gave talks for free, contributed to OSS projects and also had my own OSS projects

Talks Given

Mostly talks at meetups and companies

  • 2023

    ZIO test vs Scalatest

    At vandebron I gave a talk to compare zio-test vs scalatest

  • 2023

    refined

    During amsterdam.scala meetup at vandebron I gave a introduction talk to refinement types in Scala

  • 2023

    Rust introduction

    Gave a Rust introduction talk at Flock.community

  • 2022

    Bazel

    At amsterdam.scala I gave an introduction talk about Bazel and Scala

  • 2020

    cats

    At DHL I gave a talk about the functional programming library cats in Scala

  • 2018

    http4s

    At functional rotterdam meetup I gave a talk about http4s, a functional http server/client library written in Scala

Open Source Projects

Public work and contributions available online.

  • 2018

    septic

    Small utility library to perform model based property based testing on tagless final algebras in Scala

  • 2018

    goedverhaal

    Small proof of concept of a Monad which includes lazy compensating actions. This means, when a computation fails it will attempt to roll it back

  • 2018

    itinere

    A eDSL (embedded domain specific language) in Scala to describe HTTP endpoints. From these declarations you can implement a server/client or generate OpenAPI docs

  • 2017

    flumina

    A native Kafka driver written from the ground up, so encoding/decoding messages from and to the Kafka broker, multiplexing, etc

  • 2017

    formulation

    A eDSL (embedded domain specific language) in Scala to map data structures to Avro encoders, decoders and schemas

Worked for

I served these employers to be successful in the digital world

Vandebron
Vandebron is a Dutch green energy marketplace that connects households and businesses directly with local renewable producers—like farmers with wind turbines, solar panels, or biogas—without owning any generation assets.
DHL
DHL German international courier, package delivery and express mail service. I've worked at DHL on several high-end web applications.
ING
The ING Group is a Dutch multinational banking and financial services corporation. I've worked at ING on approval software.
Veon
VEON is a Dutch-domiciled multinational telecommunication services. It predominantly operates services in the regions of Asia, Africa and Europe. I've worked at VEON on the top up transactional systems.
Malmberg
Malmberg is a Dutch company which creates educational software and books for schools. I've worked on Malmberg on a content management system (CMS) for eductional software.

Certified

Driven to keep up with latest trends and technologies

Nielsen Norman / Interaction design
Nielsen Norman Group, an elite firm dedicated to improving the everyday experience of using technology. I took courses on interaction design with the focus on apps.
Machine Learning by Andrew Ng
Machine learning is the science of getting computers to act without being explicitly programmed. In the past decade, machine learning has given us self-driving cars, speech recognition, web search, etc.
CKAD - Certified Kubernetes Application Developer
Be able to define application resources and use core primitives to build, monitor, and troubleshoot scalable applications and tools in Kubernetes.