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Lookup: Validation and Formatting

Twilio Lookup can help you check that phone numbers you receive from your users are real. It can also provide you with the local format of an international phone number.

This guide will show you how to perform both kinds of lookups. You can skip to the carrier and caller name guide to learn about other information Lookup can provide about a phone number.

Validate a national phone number

Given a national phone number and an ISO country code, Lookup will confirm the phone number is valid and return the number in its E.164 format.


        If the number is invalid, this request will return an HTTP 404 status code.

        If you plan to store the phone number after validating, we recommend storing the full E.164 formatted number returned in the phone number field. Most other Twilio services require the E.164 format for phone numbers.

        Format an International Phone Number

        If you send Lookup an internationally formatted phone number, you can get the correct national format for that phone number from the national format field.


              Though most other Twilio services require the E.164 formatted number, the national format is often better to display to end users.

              Lookup can tell you even more about a phone number. Check out the carrier and caller name guide to learn how.

              Andrew Baker Kat King Kelley Robinson
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