To override the Content-type in your clients, use the HTTP Accept Header, append  the .json suffix or  ?format=json
To embed the response in a jsonp callback, append ?callback=myCallback
        
        HTTP + JSON
         The following are sample HTTP requests and responses. 
            The placeholders shown need to be replaced with actual values.
POST /json/reply/QuickLookup HTTP/1.1 
Host: doapigw.baasbv.nl 
Accept: application/json
Content-Type: application/json
Content-Length: length
{"DocumentID":"00000000-0000-0000-0000-000000000000","DocumentFieldID":"String","RegistrationProfileFieldID":"String","LookupValue":"String","DependableFields":[{"DocumentFieldID":"00000000-0000-0000-0000-000000000000","Value":"String","ShadowValue":"String","IsModifiedByUser":false}],"ApplyOptionalFilters":false}
 
HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: length
{"NumberOfAllRecords":0,"Values":[{}],"QuickAddOptions":[{"Name":"String","EntityType":"String"}]}