Hi, I'm Tijn Kersjes [tɛin kɛʀʃʏs]

Full-stack coffee lover

I am a software developer from Amsterdam. Mostly writing (some flavour of) JavaScript, interested in anything functional or reactive, and rarely seen without a cup of coffee. After office hours I like to tinker around with esoteric compilers or hack on old Game Boy hardware.
Date of birth
7 April 1993
Amsterdam, the Netherlands
Reaktor May 2017 – Today
Software engineer at a technical consultancy firm.
  • Worked on the React/SPA rewrite of adidas.com
  • Built TypeScript microservices to support Yeezy drops.
  • Created React-Native prototypes for an IoT startup.
  • Improved interviewing practices and hired new consultants.
Konnektid Dec 2013 – Feb 2017
Full-stack web developer at a local startup connecting neighbours to learn and teach skills.
  • Developed frontend in React (with Flux/Redux).
  • Written backend systems in Node, using MongoDB and Neo4j.
  • Implemented Event Sourcing architecture with RabbitMQ.
  • Managed deployments with Ansible / GCP.
  • Employee of the week for 6 consecutive weeks.
CreativeCrowds Oct 2013 – Dec 2013
iOS application development and support.
Indievelopment Jan 2012 – May 2015
Organised an annual game development conference, hosting 500 visitors during its last edition.
DGDARC Jan 2012 – Dec 2014
Board member at the Dutch Game Development And Research Club.
driezesnul Sept 2010 – May 2011
Web application research & development for a local design agency. Making small prototypes to demo the AJAX and GeoLocation possibilities that smartphones (at the time) just introduced.
Utrecht University 2011 – 2015; 2016 – 2017
BSc Computer Science
  • Specialisation: Game Technology
Sintermeerten College 2005 – 2011
Secondary school
  • Orientation: Science and Engineering
  • English language CEFR level C1
Platforms & Libraries
Node.js, Deno, React, Redux, io-ts/fp-ts
TypeScript, JavaScript, Python, PHP, C#
Backend & Databases
RabbitMQ, MongoDB, CouchDB, DynamoDB
Infra & Cloud
Heroku, Docker, Ansible, Jenkins, GCP, AWS
GambiConf Lisbon Sept 2022
Writing a Game Boy compiler in Forth (video).
Fork Pull Merge Push Mar 2020
Finding the Corner of the Internet You Love with Amsterdam Hackers.
An episode for the Reaktor podcast, available on Spotify and Apple Podcasts.
FOSDEM Feb 2019
GBForth: Using Forth to understand the Game Boy. Video and slides.
AmsterdamJS Dec 2018
Codemods: Refactoring JavaScript with JavaScript. Video and slides.
FortBoy Mar 2022
A procedurally generated text adventure made during 7DRL.
Straying Alive Apr 2020
A game I made to learn about ECS during Ludum Dare 46.
Delisp Apr 2019
A delightful Lisp for JavaScript.
Far From Home Jan 2019
An experimental game based on latency. Made during the Global Game Jam.
GBForth Jul 2018
A Forth-based Game Boy development kit.
Brain Teaser Jun 2006
Educational game, placed second in the Make-a-Game competition.
What's happening?
Roll for initiative
Personal blog