I want to ask all the front end development experts here. How do you implement interactions like this https://dribbble.com/shots/5708399-Christmas-Collisions ? What are the tools, tech and strategy you use, and what are the challenges you face ?

Looks like either a combination of a physic engines like @tall-postman-9284 mentioned and WebGL ( i.e. three.js) or could be a physics engine with 3D support (matter js AFAIK does not support 3D rendering) ... check out https://github.com/bebraw/jswiki/wiki/Physics-libraries#3d to find a bunch of 3D physics engines

Thanks @abundant-jackal-54634, let me try to understand that dev/technical stuff. Basically, I wanted to have an overview/structure/ architecture that devs decide while developing such concepts, and @tall-postman-9284 has somewhat mentioned it in the comment.