|200 - OK
||Everything worked as expected.
|400 - Bad Request
||Bad input parameter. Error message should indicate which one and why.
|401 - Unauthorized
||No valid API key provided.
|403 - Forbidden
||Maybe there is permission denied for the user to that service
|404 - Not Found
||The requested resource doesn't exist.
|405 - Method Not Allowed
||The resource doesn't support the specified HTTP verb.
|422 - Unprocessable Entity
||Input parameter required, given input can't processable, input validation failed
|500, 502, 503, 504 - Server Errors
||Something went wrong on Doorhub's end. (These are rare.)