Non-VoIP number

A phone number from a real mobile carrier range, as opposed to one issued by an internet telephony provider.

A non-VoIP number sits in a numbering range that national plans allocate to mobile carriers. Platforms can look up a number's range before sending a code, and many reject VoIP ranges outright because VoIP numbers are cheap to obtain in bulk and correlate with abuse.

"Non-VoIP" is therefore the quality bar for SMS verification: a number that passes the range check and receives the code like an ordinary handset. MarioSMS rents from real carrier mobile ranges for exactly this reason.