Let’s say that you want to send an offer to your customers which is active only for today. You decided that the best time to send the SMS is at 17:00.
It is important for you that the customers will receive the SMS within the day and before closing hour. Your boss does not want any message to be delivered the next day because the offer has ended.
After you send the SMS, the network tries to deliver the message for 48 hours. For example, if a mobile is switched off, the system tries to deliver it within this period.
With Validity period you can specify for how long the system will try to deliver the message to your customers. So, if the closing hour is at 22:30 you need to put the validity period of 5 hours and the pending SMS will be marked as Undelivered after 5 hours from sending.