# Carrier lookup

A carrier lookup is a query that returns the carrier and line type (mobile, landline, VoIP) of a phone number; apps run it before sending an OTP.

## What is Carrier lookup?

A carrier lookup is a query that returns the carrier and line type (mobile, landline, VoIP) of a phone number; apps run it before sending an OTP.

## What apps do with it

Refuse VoIP, rate-limit prefixes, and match the number's country with your location. It is why the same app accepts one country and refuses another.

Source: https://smsnitro.com/glossary/carrier-lookup