As noted in the Message Structure section, if there is an error with a request, you will receive a response which has a HTTP-like responseCode that will indicate what the error was, and the responseMessage will describe what the error was.

For example:

{
  "type": "response",
  "requestId": "1",
  "responseCode": 500,
  "responseMessage": "Internal Server Error"
}

In certain cases (such as when you client is streaming audio to the WebSocket) you may receive a notification indicating that an error has happened during processing.

For example:

{
  "type": "notification",
  "notificationType": "internal_server_error"
}