YAML vs JSON

YAML is best suited for configuration where JSON is better as a serialization format or serving up data for your APIs.

YAML is by no means a holy grail or a replacement for JSON - you should use the data format that makes the most sense for what you are trying to accomplish.

But in some cases, YAML has a couple of big advantages over JSON, including the ability to self reference, support for complex datatypes, embedded block literals, comments, and more.

Write you configuration files in YAML format where you have the opportunity - it is designed to be readable and editable by humans.

JSON, in contrast, is only designed to be human readable - intentionally lacking features to support editing. Lets start with lack of comment support - this is intentionally left out of the JSON spec because its not what the format was designed for.

A big win for YAML is that it does support comments. This is very useful especially when you use it for configuration. For data interchange, many of YAMLs features lose their appeal.

YAML parsers are younger and have been known to be less secure.

JSON vs YAML

JSON wins as a serialization format. It is more explicit and more suitable for data interchange between your apis.

JSON ships with a far simpler spec than YAML. You can learn JSON a lot faster than you can learn YAML, because it is not nearly as robust in its feature set.

YAML is a superset of JSON, which means you can parse JSON with a YAML parser.

Try mixing JSON and YAML in the same document: [..., ..] for annotating arrays and { "foo" : "bar"} for objects.