Hi there!

My name is Koen van Gilst and I'm a JavaScript developer who loves creating funny Twitter bots, educational games for my kids and other creative stuff.

Have a look at my profile if you're interested in working with me or else feel free to browse through my experiments and projects below.

I keep a blog here.

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

Have fun!

Peter and the Wolf

I created this PWA for my kids, based upon the classical piece "Peter and the Wolf" by Prokofiev. Turns out that making large mp3s available offline was harder than I thought.

Play + Source [2018]

Finding Nora

I created this fun little PWA for my daughter Nora to help her spell her name. She loved it, hope you do too!

  • 🚀 create-react-app + TypeScript
  • ⛺ full offline support
  • 🎺 web audio for sounds
Play + Source [2018]

MyTommy Loyalty App

For Tommy Hilfiger I worked in a Scrum team as a fullstack JavaScript developer on their loyality app MyTommy.

Demo page (in Dutch) [2018]

Audio Books Player

For Dedicon I created a player for their audio books collections, it's designed specifically for users with visual impairments. The player also has a karaoke function that highlights the text currently being read for children with dyslexia.

Demo page (in Dutch) [2017]

Star Wars or Star Trek?

Why not both? Using just CSS and a bit of JavaScript I recreated these classic science fiction intro's.

Star Trek + Source
Star Wars + Source [2017]

Shortcut Trainer

Quickly learn the 10 most commonly used keyboard shortcuts for the translation CAT tool MemoQ. Weekend project using React.

Demo + Source [2016]

LaTeX Letters

Creating beautiful PDF letters using LaTeX in a Docker container on a server.

Source code [2016]

Rush hour timelapse

A Twitter bot that creates daily timelapse videos of the traffic jams in The Netherlands. No longer active, but you can still see some of the old timelapses.

@altijdfiles + Source [2016]

Term Search

A terminology search engine for translators. Currently only German-Dutch terms. Work in progress. [ No longer online ]

Technologies: NodeJS, Express, MongoDB, Loopback, ReactJS.

Source [2016]

Help Terence!

A Twitter bot raising emoji money for his trip around the world. Fun little experiment with social media and Twitter bots. [ No longer active ]

Technologies used: Express, MongoDB.

@helpTerence + Source [2016]

Word to Line Prices

A simple web app for translators that converts a price per word to a price per standard line (55 characters).

Visit the app + Source [2016]

Wikipedia edits by the Dutch government

Twitter bot inspired by @congressedits that monitors and Tweets any edits made to Wikipedia by the Dutch government.

@OverheidEdits + Source [2013]


I once wrote this program in assembly, but this time I wanted to do it in Javascript.

Demo [2013]

Dawkins' Trees

For this web app I've tried to recreate (in part) the program Richard Dawkins describes in his book The Blind Watchmaker.

Demo [2013]