What are the development tools for ST hub?

I see lots of discussion about code developed in an effort to make the Leviton zone and scene controllers work. These are written as if one had some means to alter/add code to the ST hub. What is the process to do that and what tools does one need. Is there a compiler for the hub?

The tools don’t actually put code on the hub (at least for the current v1 hub) but run in the SmartThings cloud. Click that “Developers” link in the upper right on the page and that will get you pointed in the right direction: