json APi Error Objects

A Basic Error Object

In the response below, the server is indicating that it encountered an error while creating/updating the resource, and that this error was caused by an invalid "first-name" attribute:

HTTP/1.1 422 Unprocessable Entity
Content-Type: application/vnd.api+json

{
  "errors": [
    {
      "status": "422",
      "source": { "pointer": "/data/attributes/first-name" },
      "title":  "Invalid Attribute",
      "detail": "First name must contain at least three characters."
    }
  ]
}

Every member in an error object is optional, but all help the client by providing extra details.
The source member is used to indicate which part of the request document caused the error.
The title and detail members are similar, but detail is specific to this occurrence of the problem, whereas title is more generic.
The status member represents the HTTP status code associated with the problem. It’s very helpful when multiple errors are returned at once (see below), as the HTTP response itself can only have one status code. However, it can also be useful for single errors, to save clients the trouble of consulting the HTTP headers, or for using JSON API over non-HTTP protocols, which may be officially supported in the near future.