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.