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Phone validation
Mobile vs landline vs VoIP: how to detect line type
PN
Not all phone numbers are equal. A mobile, a landline and a VoIP number each demand a different approach — and texting the wrong type wastes money. Here's how line type works.
The three line types
- Mobile — can be called and texted; ideal for SMS.
- Landline — can be called, not texted.
- VoIP — internet-based; often used for fraud or throwaway signups.
Why it changes your strategy
Routing matters: send SMS only to mobiles, route landlines to your dialer, and flag VoIP numbers for extra scrutiny. Getting this right cuts failed texts and wasted dials.
VoIP as a risk signal
A surprising share of fraudulent or throwaway signups use VoIP numbers. Detecting them lets you add friction or verification before they reach a campaign — much like flagging disposable emails.
Detecting it at scale
BounceBlock returns line type for every number in your upload, so you can segment by type and reach each contact the right way.
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