Phone validation and compliance
What is a carrier lookup?
Also called: phone carrier lookup, LNP lookup, number lookup
A carrier lookup queries telecom data to find which carrier a phone number is assigned to and what line type it is, taking number porting into account where the data covers it. It answers which network a number belongs to; it does not show whether the phone is switched on or who is using it.
Numbering-plan data only tells you which carrier a block of numbers was originally given to. Once a number is ported, that is wrong. A carrier lookup uses porting data to return the current carrier, which is what SMS routing and line-type decisions need.
Lookups are paid per query by the data provider, so they are usually run on numbers that already passed a format check, not on raw input.
A carrier lookup is not an HLR lookup. It reads databases about the number, not the live state of a handset on a mobile network.
Example
+14155550123 → carrier: Example Wireless, line type: mobile.How SimpleVerifier handles it
On the Email + Phone plan, valid numbers get a live carrier lookup through Telnyx (5,000 a month; failed lookups do not count). It returns phone_carrier and phone_line_type. It does not tell you a number is in service or on WhatsApp.
Go deeper
Sources
By SimpleVerifier Team · Last reviewed 2026-10-13 · All 50 glossary terms