Let’s start with the good parts. It’s not XML. Being born as a data interchange format from the mind of Douglas Crockford it shines for its simplicity in both the definition and easiness in parsing. That’s pretty much it. As a configuration tool the only good thing I can say is that many people are accustomed to it, and usually already know its rules.
As popular as it is the JSON format has started to be overused, especially for letting users to configure stuff (that’s the point of the article). The first thing to notice here is that JSON is not intended to be used that way, instead we can quote from the official page:
What I’d like to highlight is that JSON is a compromise between write/readability for both humans and machines. A data interchange format can easily be almost unreadable to humans, that happens all the time with binary formats but a configuration format should instead be biased towards humans.
But what’s wrong with JSON?
I see three things that make JSON fail as a configuration format:
Lack of comments
The absence of comments is perfectly fine in a data interchange formats where the payload will probably travel on wires and needs to be as tiny as possible. In a configuration format conversely it’s plain non-sense as they can be used to help the user explaining each configuration option or for the user to explain why he chose a particular option.
While JSON is quite readable when properly formatted, this good practice is not enforced by the format itself, so it’s up to coders good will to add returns, tabs and spaces in the right places. Lucky enough they usually do.
YAML is a human friendly data serialization standard for all programming languages.