Hi, I'm Koen!

I'm a passionate & entrepreneurial JavaScript developer from the Netherlands who likes to push the web beyond it's limits. I specialize in modern frontend using React & Svelte and I also feel at home on the backend using Node/TypeScript.

I'm interested in helping inspiring companies create innovative web apps that users love.

You can find me on Github, LinkedIn and Twitter or send me an email.


  • Platforms: Web, Node.js, Mobile (iOS)
  • Languages: JavaScript, TypeScript, HTML5, CSS3
  • Frameworks: React, React Native, Redux, Express, Next.js, Svelte, Sapper, jQuery
  • Tooling & Testing: react-testing-library, Webpack, Lerna, Babel, Jest, Nock, Detox, Cypress, Git, Unix
  • Knowledgeable: CI/CD, Testing, Monorepos, Single Page Apps, Accessibility, Server Side Rendering, Progressive Web Apps, Internationalization
  • Services: Docker, Gitlab CI, MongoDB, Postgresql, BuddyBuild, Mixpanel, Google Tag Manager, Heroku, AWS, Google Cloud, Jira, Sentry, Bugsnag

Notable client projects

  • For Stichting Dedicon I created a player for their audio books collections. It's build specifically for users with visual impairments. The player has a karaoke function that highlights the text currently being read, which helps children with dyslexia. Read more about the Online Player here...
  • For Tommy Hilfiger I worked as a fullstack JavaScript developer on their loyality app MyTommy. The app is build in React Native for both iPhone and Android, with a restful Node/Express API on the backend. Read more about MyTommy here...
  • The Dutch Chambre of Commerce (KVK) has a high traffic website (about 1.5 million visitors per month) with applications that help companies do business in The Netherlands. As a frontend engineer I'm part of the team building and deploying the new Online Registration web app, which makes it possible for Dutch entrepreneurs to register their business completely online.


  • M.A. in Philosophy, Utrecht University (cum laude).
  • Minor in Computational Science, Utrecht University.
  • Erasmus Student Exchange, Universit├Ąt Regensburg (Germany).


References, code samples and a copy of my resume upon request.