How can I add more mobile numbers to my Sandbox whitelist?

To whitelist extra numbers, log into https://unify.smsgateway.center and check the dashboard. Find the “you are operating within a Sandbox Account!” alert at the top and click “Whitelist Number.” Enter the new number in the modal that appears—an OTP will be sent to it. Input the OTP to validate, and the number is added. You can now test SMS to it, expanding your evaluation of our SMS gateway.