Philippe, I would encourage you to just use Groovy with JsonSlurper in the ExecuteScript processor. Its a blazing fast parser actually.
http://groovy-lang.org/json.html http://docs.groovy-lang.org/latest/html/gapi/groovy/json/JsonSlurper.html Thad +ThadGuidry <https://www.google.com/+ThadGuidry>
