Phone number line type

A phone number's line type is the kind of service the number belongs to: a mobile line, a fixed (landline) line, a VoIP service, a toll-free or premium-rate number, and so on. It decides whether a number can receive SMS, how much a call to it costs, and which regulations apply when you contact it.

#Which line types exist?

MobileValidate's carrier lookup returns line_type with the values below. They follow the categories used by common numbering-plan libraries.

#How is line type determined?

There are two ways, with different reliability.

From the numbering plan. Every country publishes which ranges are used for which services. In the UK, for example, numbers starting 07 (other than 070 and 076) are mobile, and 0800 numbers are toll-free. This works offline and costs nothing, but it describes the range, not the current service. It fails in countries where mobile and landline numbers share ranges (the US and Canada, which is why fixed_line_or_mobile exists), and it fails when a number has been ported to another kind of service.

From network or carrier data. A carrier lookup reads current data about the specific number. It can tell you that a number in a geographic range is actually served by a VoIP provider, or that a former landline now belongs to a mobile network. In the US, where numbers can be ported between landline, wireless and VoIP services, this is the only reliable way.

#Why does line type matter?

• SMS cost and delivery. Texts to landlines, toll-free and premium-rate numbers usually fail, but many providers still charge for them. Filtering by line_type before a send avoids that. See SMS cost reduction.
• Fraud signals. A cluster of sign-ups from VoIP numbers, or OTP requests to premium-rate ranges, are classic patterns of fake accounts and SMS pumping.
• Compliance. Some calling and texting rules differ between wireless and landline numbers. In the US, for example, the TCPA's consent rules for autodialled calls apply specifically to wireless numbers.
• Data quality. A "mobile" form field that holds a landline or toll-free number tells you the entry needs another look.

#How do I check line type with MobileValidate?

Use the carrier lookup (all countries, real time or bulk) or the US and Canada carrier lookup (bulk). Both return line_type and the current carrier. When we hold no data, the answer is unknown and you aren't charged.