Ronald Fischer wrote:

The documentation of the JSON stdlib class (i.e. http://ruby-doc.org/stdlib-2.2.5/libdoc/json/rdoc/JSON.html) is missing a description, what the user has to do to provide JSON serialization for his own classes (i.e. description of the to_json and from_json callback is missing).

from_json?

Maybe you're confusing it with Rails?

ActiveModel::Serializers::JSON#from_json