The proliferation of configuration languages is far older than JSON. There's just a couple inherent problems with the notion of a universal configuration langu

The proliferation of configuration languages is far older than JSON. There's just a couple inherent problems with the notion of a universal configuration language... First not all software has the same type of configuration requirements. I don't mean different schemas, I mean some measure of "configurablity". You have things like nginx or varnish that are configurable enough that configs are almost (or actually) programs. You also have programs where you need to store a few KVs that will be inserted into strings at some point and that's it. That wide range of "amount of possible configuration" is hard to capture easily in a single configuration language. Next you have a wide range "flatness" - that is if the configuration needs to be a list of kvs (optionally w/ sections) or if you need a tree or graph shape, or something weird. Finally there's the whole preference and "style" thing. Writing a config language has an appeal to it - it's a fairly straight-forward thing to do (at least seemingly, until you hit the edge cases), and it's infinitely bikeshedable. In a similar vein, it seems to devolve into this sort of thing quite often: https://xkcd.com/927/ https://xkcd.com/927/ This is one of those situations where it's nice to be "old" - I like that I only have to know a handful of config formats these days, rather than keeping track of each program's bespoke config format.