From the jQuery documentation - http://api.jquery.com/jQuery.ajax/
contentType When sending data to the server, use this content type.
dataType The type of data that you're expecting back from the server. If none is specified, jQuery will try to infer it based on the MIME type of the response
"text": A plain text string.
So you want contentType to be application/json and dataType to be text:
$.ajax({
type : "POST",
url : /v1/user,
dataType : "text",
contentType: "application/json",
data : dataAttribute,
success : function() {
},
error : function(error) {
}
});