JSON REST Webservice Error Responses

Over the years I've seen many formats for error responses from JSON formatted REST webservices.  Well, there's a draft standard.

The quick answer is:

Error Response


   In the event of an error, a 4xx or 5xx HTTP status code SHOULD BE
   expressed in the response, with an entity body containing an error
   object adhering to the following structure:

   {
       "error": number,
       "reason": string,
       "detail": string
   }