Phone validation and compliance
What is a VoIP number?
Also called: virtual number, internet phone number, non-fixed VoIP
A VoIP number is a phone number delivered over the internet rather than through a mobile network or copper line. Some are tied to a business phone system at a fixed address; others can be created online in minutes. That ease is why many signup flows treat VoIP numbers as higher risk.
VoIP numbers look like any other number. In the US they come from the same area codes as mobile and landline numbers, so only a carrier lookup can tell you a number is VoIP.
Whether to accept them depends on what you are doing. Plenty of real businesses run on VoIP, so blocking them from a B2B call list removes good leads. On a consumer signup form, where a number is meant to tie an account to a person, VoIP numbers are where abuse tends to concentrate.
Many VoIP services cannot receive SMS from short codes, so a VoIP flag is also useful before a text campaign.
How SimpleVerifier handles it
On the Email + Phone plan, the live lookup returns phone_line_type: voip for numbers the carrier data identifies as VoIP. The numbering plan alone cannot tell.
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Sources
By SimpleVerifier Team · Last reviewed 2026-10-13 · All 50 glossary terms