You can expect all errors to have the same JSON response structure. For example here is what a 404 will look like:
HTTP/1.1 404 Not FoundContent-Type: application/json{"name": "Not Found Exception","message": "The requested resource was not found.","code": 0,"status": 404,"type": "NotFoundException"}
A 500 error may look like this:
HTTP/1.1 500 Internal Server ErrorContent-Type: application/json{"name": "Internal Server Error","message": "Something very bad happened","code": 0,"status": 500,"type": "InternalServerErrorException"}