Dennis Reimann:

The UIengine is a tool to build pattern libraries and documentation for design systems. It helps designer and developers to work closely together and offers features to boost their productivity.

Alternatives already exist in the ecosystem (Fractal, Storybook, etc). Why reinvent the wheel?

Most of the existing tools focussed on the component development, but lacked ways to also provide good documentation. Some were limited to using a specific templating language or framework, which was suboptimal for me: As a freelancer I am working on many projects and each one has its own set of constraints and requirements. I wanted to build a tool with an open source license, which I could use and extend with every project I work on.