{MSISDN} – will be replaced with the recipient's phone number
{MESSAGE} – will be replaced with the actual SMS text
https://my-api-endpoint?phone={MSISDN}&message={MESSAGE}&sender=your_senderid&token=your_token
https://my-api-endpoint?phone={MSISDN}&text={MESSAGE} ( This is the bare minimum webhook URL)
{MSISDN} and {MESSAGE} placeholders. These are essential for delivering the SMS correctly.