If you are using the API / Gateway to send bulk SMS you can collect your delivery reports from the server, which is a good way of removing bad numbers from your data.
It is important to understand the difference between getting a “failure” (or success) message at the API/Gateway and a delivery report.
The HTTP GET response from the gateway only confirms that the number and message appear to be in the correct format this does not mean that the number exists.
Delivery reports confirm to you what has actually happened to the message, the following outcomes are possible:
“DELIVERED”,”REJECTED”,”FAILED”,"NOT-UK",”PENDING” and no report at all.
|Delivered||The message has been delivered to the handset .|
Rejected by the relevant operator and did not attempt to deliver it
The number isn't in use, but may have been and might be again in the future.
Trying to send a non UK number when your account isn't internationally enabled.
Waiting for the report from the networks. Can take up to 3 days