How to import data from Attentive to Klaviyo

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You will learn

Learn how to import your data from Attentive to Klaviyo for your SMS program. When migrating from Attentive, you can upload your existing list of SMS subscribers to Klaviyo to start building out your SMS marketing strategy right away.

Importing your SMS contacts allows you to centralize customer data so that you can leverage Klaviyo’s robust analytics and tailor your customers' experience with SMS-integrated flows, emails, and push notifications.

Before you begin

Before you start the import process, you must: 

  1. Enable SMS in Klaviyo
  2. Set up you sending numbers for all countries you want to send to

Otherwise, consent for your imported customers will not be stored. 

Check this guide on migrating from another SMS provider for instructions.

Export SMS subscribers from Attentive

Before you begin migrating your SMS contacts from Attentive into Klaviyo, it's important to clean your list. Otherwise, when you go to import, you have both opted-in and opted-out subscribers in your upload. It is against Klaviyo's Terms of Service to market to contacts who have not explicitly opted-in to receive SMS communication from your business. 

Klaviyo identifies opt-in subscribers as those who have a phone number and an SMS Consent Timestamp associated with their profile. Klaviyo will only send SMS messages to contacts who have both a phone number and an SMS Consent Timestamp stored within their Klaviyo profiles. 

Attentive requires that you reach out to your account representative to receive an export of your SMS subscribers as a CSV file. It is not currently possible to export the file yourself. When migrating to Klaviyo, plan for turnaround time for Attentive to complete this request.

We recommend asking your account rep for a CSV export containing all contacts, including (if available): first name, last name, email address, phone number, and the consent timestamp. At a minimum, you will require the SMS subscriber’s phone number and consent timestamp.

If the CSV file you receive contains contacts who have opted out of SMS messaging, as indicated in the opt_out column of your export, you will want to filter these contacts out before proceeding with an import.

Format and upload subscriber list CSV

Carefully format your CSV file before importing it into Klaviyo to ensure that your contacts are imported smoothly and accurately.

  1. Though not required, you will likely want to include these columns in your import, if they have been included in your CSV file:
    • first_name
    • last_name
    • email
  2. The phone number column is required to import your SMS contacts. Check the format of the phone numbers in your CSV file. Phone numbers must be in one of the following formats:
    • E.164 (e.g., +12345678910)
    • RFC966 (e.g., +12-34-567-8910)
    • E.123 national (e.g., 12345678910) 
    • international formats (e.g., +12 345 678 910)
  3. Klaviyo requires anSMS Consent Timestamp column at the time of import, so you will need to rename the appropriate column heading. Locate the column heading named created, delete the text, and rename it SMS Consent Timestamp. Doing so allows your import to automatically map the values to the correct field in Klaviyo. Timestamps need to be specifically formatted or Klaviyo will not recognize them as timestamp fields. Attentive exports timestamp data in the format MM-DD-YYYY HH:MM:SS by default. You may wish to format these data fields as dates to ensure proper import. The date format MM/DD/YYYY HH:MM:SS is supported by Klaviyo by default. For additional supported timestamp formats, check out our guide to acceptable formats.
  4. Indicating the country (e.g., USA, United States, or US) for the phone number is also required to import SMS contacts. You can only import consent for contacts in countries where Klaviyo SMS is available. Having a column labeled "Country" is the best practice, but the import will also work if you add the country code to the phone number instead (e.g., +1 for the USA) like in many of the number formats shown above. To do so, add an apostrophe and a plus sign before the country code so that it's formatted correctly (e.g., '+12345678910). 
  5. Now, it's time to import your list - consult our guide for step-by-step instructions. 

Attentive form troubleshooting

When redirecting a custom or third-party form to a Klaviyo list, it is expected that the form will adhere to your list’s double opt-in behavior. By default, Attentive forms will use a members endpoint from the V2 list API. This is equivalent to uploading a CSV of opt-ins into a Klaviyo list and we would not trigger a double opt-in message to be sent, even if it is enabled at the list level.

In order to have your Attentive form adhere to the list opt-in settings, the endpoint needs to be changed to the subscribe endpoint. We will then treat it as though the user signed up through a sign-up form and respect the opt-in settings. This redirect must be done by Attentive. You should reach out to Attentive to switch these endpoints on the Attentive end.


You've now learned how to import data from Attentive to Klaviyo.

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