I use a lot of JSON and YAML via libvariant [0], a set of C++ libraries. e.g. the core class Variant is a JSON-ish object implementation; there are pluggable Serializers & Deserializers, etc.

Libvariant includes a command line tool, varsh ("Variant shell"), that can schema-validate JSON and YAML documents.

[0] https://bitbucket.org/gallen/libvariant