A virtual number is a phone number rented out by a provider that holds number blocks for internet calling and messaging, rather than one tied to a SIM card or a physical line. In Spaw it has a narrower, checkable meaning: the regulator's allocation table shows the number's block held by a virtual-number wholesaler or VoIP provider.
What Spaw answers
is_virtual is true when the holder of the number's block is on Spaw's classification list of virtual-number wholesalers and VoIP providers, false for any other block the table lists, and null where no regulator table lists the number's block. A true answer raises the virtual signal, +40 on the risk score, and risk_signals names the table that answered. The default SMS policy does not refuse it on its own, because +40 is within the default ceiling of 60.
In North America the holder also settles the line type, since the plan cannot tell mobiles from landlines (see NPA/NXX). A number in such a block answers line_type: "voip" with line_type_source: "block_allocation", and the plan-based voip signal (+30) does not fire beside it. In a pooled US code the holder is that of the number's own thousands-block where NANPA lists one; in Canada it is the code holder. Elsewhere the plan's type stands: a British geographic number in a block Ofcom's table gives to a VoIP provider answers fixed_line with is_virtual: true. The test number +1 202 555 0102 answers is_virtual: true, line_type: "voip" and a score of 40.
How common it is
NANPA's tables of 26 September 2026 put 370,513,000 of the 1,883,208,000 allocated US numbers, 19.7%, in blocks held by VoIP providers on the classification list. The numbers published by SMS-receiving websites lean much further that way: of the 25,659 numbers with a US area code on the two open lists Spaw synced on 24 September 2026, 16,589 (64.7%) sit in such blocks. The first is a share of the regulator's table and the second a share of the listed numbers, neither of traffic, and both are lower bounds, since they count only holders on Spaw's classification list: 45.3% of allocated US numbers, and 15.9% of the listed ones, sit with holders the list does not classify. The phone statistics page re-measures them weekly, and each country's table is described under phone facts by country.
What it does not mean
Spaw does not separate fixed from non-fixed VoIP. Some lookup services split the two: fixed VoIP, a virtual number associated with a physical device, and non-fixed VoIP, one obtained online without a physical device. The regulator tables record only who holds the block, so a business line on a hosted phone system and a number rented through an app answer the same.
The table records the original allocation, never who serves the number today. A number ported out of a provider's block keeps is_virtual: true, and one ported into it does not.
Plenty of people and businesses use virtual numbers. The weight says a number is cheap to obtain and to let go, not that the person typing it is lying. For a one-time code, read it beside the account's own range_burst count and the SMS-receiving signals.