Unity editor extension - create drag and drop (similar to Buildbox)

I want to create a editor extension so I could create a app similar to Buildbox but in unity. Is it possible to create the drag and drop, features (game templates, effects, logic, nodes, etc) available in Buildbox. Is so can u plz give any reference, start point, guide to achieve the target.
Thanx

Never heard of BuildBox, but the Unity editor is completely extendable. Auntie Google gave me these links when I asked her: