Holdkey is created by Bas van Reek. In 2010 a friend asked how to type characters with accents, i had no idea other than the fuzz with alt codes. That's when the idea was born to create Holdkey.
As of writing it's many months and hundreds of hours of programming later. Holdkey is there and works very smooth, i think it's a great peace of software. Holdkey is located in Amsterdam, The Netherlands.