Hi @joe,
When sending a job request to us by API, whether in Sandbox or Production, you will receive back a standard HTTP response which indicated whether the request was a success or not. You can find more details of these responses in our API docs.
Sandbox and Production accounts are separate and have separate API credentials, you can find out more about account creation and our environments in the getting started page of our API docs.
We are able to handle sending SMS updates to your end customer, for more information on this topic please see this post. Note that this SMS service is only available in our Production environment.