Every year the sticker team organizes an event during new year for everyone in Japan. This years campaign contained of a look back to see the most used stickers of 2021 and distributed points if users received new year stickers from friends. The project was very succesful and received a lot of traffic during the new years peak.

Seeing the impact this has on users when they can start using the service is very rewarding and fun to see.

Every year the sticker team organizes an event during new year for everyone in Japan. This event usually gives users who purchase a special new year sticker a Japanese Omikuji (おみくじ / Fortune). The event is custom made and usually contains a twist like a bonus for sharing the Omikuji or getting something extra when receiving a good fortune. Building this project requires a lot of effort and careful planning since millions of users will start using this when the new year starts leaving very little room for error.

Seeing the impact this has on users when they can start using the service is very rewarding and fun to see.

A highly scalable messaging system to target a set of people in a large group. It's possible to message a person or a system in a lot of different ways including text, email, phone calls or REST calls.
The system was used at the Dutch Railroads (NS) to target all personnel outside the office (including Conductors and Train operators).
It needed to follow a very strict SLA which made this a very interesting and challenging project to work on.

A cross platform multiplayer mobile game I've worked on for quite a while. I created the frontend game engine and backend server from scratch.
Creating a small abstraction layer between OS and Game engine I was able to port it to a lot of different systems. See details for all the different platforms.

A trading algorithm I created during my internship in Tokyo (Japan). The project was able to long term trade using a variety of algorithms. The program was succesfull but unfortunately never put in production.