Why apps reject VoIP numbers

What VoIP and non-VoIP mean

A VoIP (voice over internet protocol) number is one carried over the internet by a calling or texting service, rather than one that comes with a mobile or landline plan. Non-VoIP describes how a number is classed by a line-type lookup, not the phone in your hand. Steam makes the difference plain: it says “select carriers use VoIP technology in their cellular plans” and that it refuses those numbers too.

Virtual number has no fixed meaning, and each app draws its own lines. Airbnb groups “most virtual phone numbers” with VoIP services. Claude refuses “phone numbers created using apps” as a category of its own, and both Claude and OpenAI name Google Voice separately from VoIP. When you read a help page, its words are that app’s categories, which is why our table of what each app says quotes them rather than translating them.

How an app finds out a number’s line type

By asking a line-type lookup. Services exist that tell a business whether a phone number is a mobile, landline or VoIP number, and an app can run that check as soon as you type the number, before it sends anything. Steam says its system tells you when you enter a number it considers VoIP.

The lookup supplies the type. What happens next is each app’s policy, and they differ. LinkedIn accepts landlines and refuses VoIP. Telegram refuses landlines and says nothing about VoIP. Google warns only against a Google Voice number as a recovery phone. So the same number can be fine at one app and refused at the next, and none of the help pages we read says which lookup it uses or how it reads the result.

Why apps refuse VoIP numbers, in their own words

Few apps give a reason. The ones that do point at fraud and spam:

• OpenAI says landlines, VoIP, Google Voice and premium numbers aren’t supported because they are often associated with fraud or abuse.
• Steam says it can’t accept new VoIP numbers because they don’t meet its security requirements, and tells anyone refused to find a mobile or prepaid number.
• Signal, explaining why it asks for a phone number at all, says it lets people see which friends use Signal “while limiting the potential for spam”.

The help pages we read from Claude, Discord, Microsoft, WhatsApp and LinkedIn state the rule without one.

Refusals that have nothing to do with VoIP

Line type is one check. Apps refuse numbers of every type for other reasons:

• Used on too many accounts. Claude allows three accounts per number. Microsoft, TikTok, Snapchat and Discord allow one, and X allows ten. Google limits how many times a number can be used for verification without saying how many.
• Used recently. Discord puts a recently used number into a timeout and asks you to wait 24 to 48 hours.
• The wrong country. Claude takes numbers only from its supported locations, and only from people who are physically in one.
• Can’t receive texts. Telegram takes mobile numbers only, and Steam and Claude refuse any number that can’t receive a text.

What each of these looks like on screen, and what the app tells you to do, is on “this phone number cannot be used for verification”.

What a non-VoIP number changes

A non-VoIP number gets past the line-type rule, and only that rule. It doesn’t lift a per-number limit, change the country a number belongs to, or get past checks on your device or account. And it doesn’t promise a code: an app can turn a number away for reasons it doesn’t publish.

Our numbers are non-VoIP US numbers. That puts them on the accepted side of the VoIP rules above, and leaves every other check to the app. If a code doesn’t come, you can cancel within 24 hours, and the missing-code checklist covers what to try first.

Questions people ask

Why is Google Voice refused for verification?

Claude and OpenAI both name Google Voice in their lists of numbers they don’t accept, separately from VoIP. Google’s own help center says not to use a Google Voice number as a recovery phone, because you could lock yourself out of your account.

Can an app tell if my number is VoIP?

Yes. An app can run a line-type lookup on the number as soon as you enter it, before sending a code. Steam says its system tells you at that point if it considers your number VoIP.

Does a prepaid number count as VoIP?

Not by itself. Steam tells people whose number it classes as VoIP to use a mobile or prepaid number instead, and WhatsApp only asks prepaid users to check they have enough balance to receive texts.

Is a mobile number always non-VoIP?

No. Steam says some carriers use VoIP technology in their mobile plans and that it refuses those numbers, so a number on a phone plan can still be classed as VoIP.