Senior Frontend JavaScript Engineer to Refactor

I run a high school math education company and have built a working prototype of an interactive JavaScript applet engine.

The applets are deployed via GitHub Pages and embedded into iSpring courses as Web Objects.

The prototype works and is already functional. However, during development, applet-specific logic became mixed into core engine files (renderer, interaction logic, etc.).

Before scaling production, I need a senior frontend engineer to refactor and formalize the architecture so we can rapidly produce many applets per week without modifying core engine code each time.

This is primarily an architectural refactoring engagement.

Contract duration of 1 to 3 months. with 30 hours per week.

Mandatory skills:

JavaScript, HTML5, CSS, , Web Application, Front-End Development, Git