Best approach to licensing and distribute NWJS

Ive gone into NW.JS ( ) and I already have my app working, I encrypted with V8 Snapshot and now I want to distribute.
What would be the best approach to license for only 3 computers?
Any recommendations on how I can sell my app? Cannot figure out how to do it, maybe I can create an API with licenses being created everytime somone purchases or subscribe, then whenever they open the program, check the routine with the login and password?

Not sure, please help.