We make sure that arcpy has no dependencies other than those that come with arcpy. Thanks to that, arcapi is highly portable and super easy to start working with. Arcapi is for free, licensed under the Lesser General Public License 3.0 and developed in the spirit of open source software.
The bulk of arcapi development is going on on GitHub. If you have experience with GitHub and want to contribute with some code or comments, you are more than welcome to get involved in any way you see fit. This group on GeoNet, on the other hand, is the ideal place to discuss any ideas around arcapi for those who don't have/want GitHub account. Also, more generic discussions about the direction of arcapi and about best practices in using arcpy take place here.