Real mobile numbers vs VoIP numbers: why WhatsApp rejects some numbers

Every phone number in the US is registered with a line type: mobile, landline, or VoIP (voice over internet). Apps that verify you by text can look that up in carrier databases in a fraction of a second, before they even send the code.

What a VoIP number is

A VoIP number lives on the internet rather than on a mobile network. The free numbers you get from calling and texting apps are usually VoIP, and so are many numbers sold online as "virtual numbers." They're cheap to create in bulk, which is exactly why platforms are wary of them.

Why WhatsApp and others block them

• Spam and fake accounts. Numbers that can be created by the thousand are what spammers use, so many platforms refuse them outright.
• Recycling. Throwaway numbers get handed from person to person, so an account tied to one can end up in the wrong hands.
• Fraud rules. Banks, payment apps and marketplaces often require a mobile line as one of their security checks.

WhatsApp doesn't publish its exact rules and they can change, but in practice it rejects most VoIP and internet-only numbers, while real mobile numbers go through.

What a real mobile number gives you

A real mobile number is registered as a mobile line, the same type as the number on an ordinary phone plan. When WhatsApp looks it up, it sees a mobile line and treats it like one.

Airsim sells real US mobile numbers only, not VoIP. They receive texts (verification codes and any other SMS) and show them in your dashboard and email. They don't make or take regular phone calls and can't send texts, because they're built for one job: receiving your codes.

How to check a number before you rely on it

1. 1

   Ask the seller what line type it is

   If the answer is vague, or the price is pennies, assume VoIP.

2. 2

   Check whether it's yours or rented by the minute

   Short-term code numbers get reused. A number you keep is safer for any account you care about.

3. 3

   Look for a written promise

   No one controls what WhatsApp decides, so a good seller says what happens if a number is refused. Airsim replaces it free within the first 90 minutes if no code has arrived.