Accepted Phone Number Formats for SMS in Klaviyo

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Klaviyo currently accepts several different types of phone number formats for SMS marketing. In this article, you will learn about these accepted formats and tips for importing phone numbers into Klaviyo

Accepted Phone Number Formats

You can use several different formats for phone numbers with Klaviyo. Below is a chart listing the accepted phone number formats and examples.

Format Examples
E.164 +12345678900
+12 345 678 900
RFC3966  tel: 12345678900
E.123 national notation   (1234) 567 8900
  E.123 international notation  +12 345 678 900
 +1 234 567 8900

Note: the RFC3966 format comprises the prefix “tel:” followed by numbers. The numbers themselve do not need to be in a certain format.

How Klaviyo Handles Symbols and Spaces

Klaviyo can also handle certain typos and common symbols. For instance, if a phone number contains a symbol, extra space, or letter, Klaviyo will remove this when a phone number is added to a profile. The following will all be corrected to the E.164 format as +12345678900:

  • +12/345(678)*900
  • +12()*- 345678900
  • abcde()*()++12 345 678 900
  • +1-2-3-4-5-6-7-8-9-0-0

Including a Country Code

When uploading SMS consent, most phone number formats require the country code (e.g., "+1") for Klaviyo to properly accept the phone number and, if applicable, apply consent. If you don't have the country code, you need to include a column named "Country" and the appropriate values (e.g., USA) when importing phone numbers. A best practice is to always include this column. In addition, you need to include the consent timestamp

Both the images below are acceptable ways to format a CSV file for importing SMS contacts. For more details, read Upload a List of SMS Contacts


In other contexts, such as API calls, Klaviyo can also infer the country code based on profile information, such as a profile’s location, shipping, or billing address country.

If you are collecting consent through Klaviyo and have customers in multiple countries, the best option is to create individual signup forms that target customers by location and then change the default country code based on that location. Note that while you cannot currently send SMS messages to any country other than the United States, you can begin collecting consent from those in other areas. However, SMS for other countries is on our roadmap, so stay tuned!


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