JSON isn't a configuration language, it's just another data encoding format with the added benefit of being readable by humans. That and its ubiquity make it an appealing choice for stuff like ad-hoc configuration at first glance, but it's not the best choice. If you want a config language for shared human and machine consumption, use one designed for that purpose. JSON is pretty much just an encoding that is easy for humans to inspect and debug.
This. I've worked with a number of systems that "use json as the configuration language"; and in every case it's led to issues.
Given a choice it's better to have a .ini style format like the one that pythons ConfigParser will digest.
That way you can have sections, comments and you won't be tempted to have the application write things into the configuration on it's own...
