We specify our JSON-Format-Definition with the JSON-Schema.
It would be nice to validate the data directly within SOAP-UI.
Schema specification (IETF RFC Draft)
http://tools.ietf.org/html/draft-fge-json-schema-validation-00
Understanding JSON-Schema:
http://spacetelescope.github.io/understanding-json-schema/
Generating JSON-Schemas:
Validating JSON-Schemas:
http://json-schema-validator.herokuapp.com/
Using JUnit Tests rest-assured:
http://www.jayway.com/2013/12/10/json-schema-validation-with-rest-assured/