Hello, my name is Gerrit kleyn Winkel. Welcome to my website!

I am a registered Mobile App developer from the Netherlands. 

I'm working as a Professional Freelance Software Engineer for over 20 years now and started developing apps in 2010.
You can have a look at my App portfolio by selecting one of the Mobile systems mentioned on the top of this page.

You can contact me via the "Contact" page, to mail me about App improvements, suggestions or any other business that you would like to share with me.

Most of my Apps are published in the Google Play storeApple app storeWindows Phone Store or BlackBerry World


HomeWork & TimeTable app for students and teachers. Widgets for timetable and homework.


An app to keep track of your varying shifts. Including reporting, percentages and much more.


App for finding meaning of words. App available in English, German and Dutch.

Gamma Ray Calculator

App used for finding cracks in certain materials, using gamma rays. App calculates exposure time.