A customer only gets the appointment reminder or order update they were promised if the number on file can actually receive a text in the first place, and a landline or a disconnected number quietly breaks that chain long before anyone notices. Phone Validator exists to catch that earlier, checking whether a North American number is a mobile, a landline, a VOIP line or a toll free number.

Placed as a step in the middle of a Zap, Phone Validator can check a number before it ever reaches a Mobile Message action such as Send SMS, so a landline or toll free number gets filtered out instead of quietly wasting a text that could never arrive. That keeps a Zap's SMS steps reserved for numbers that can actually receive one, and it keeps delivery reports free of failures caused by the wrong number type rather than an actual sending problem.