Send Custom Properties From Postscript Popups to Subscriber Profiles in Klaviyo

Who gets this? Shops on all Postscript plans have access to this feature. Learn more about Postscript Plans.

Postscript popups continue to be a powerful (and compliant) way to collect SMS subscribers and custom properties. With an active Klaviyo integration, you can send custom properties collected with Postscript popups to subscriber profiles in Klaviyo.

Before We Begin

It's important to make sure your account is set up to properly pass data from Postscript to Klaviyo. Please review the following items before getting started.

  • In order for data to properly pass from Postscript to Klaviyo, please ensure the integration is configured correctly.
  • Make sure your Postscript popup is set up to collect emails. View these guides if you need support updating your desktop popup or mobile popup to collect email addresses.
  • Finally, make sure you've elected a Klaviyo list to forward Postscript popup-collected emails to. We discuss this in more detail below.

Forward Emails from Postscript Popups to Klaviyo Lists

To send custom properties to Klaviyo subscriber profiles, select a Klaviyo list for forwarding Postscript popup-collected emails.


  1. Select Acquisition in the side menu of your Postscript dashboard.
  2. Select the popup that you'd like to forward emails from to Klaviyo.
  3. Under the popup name, select the + Add Step/Custom Step tab. When you select + Add Step, you are able to add an additional step for subscribers to enter their email address. You can also use this second step to collect custom properties.
  4. When collecting emails, you can toggle the Forward to email app option ON and select which lists hosted by your email servicer provide you'd like to forward the collected emails and custom properties to.

Forwarding Custom Properties to Profiles in Klaviyo

Under the Form card within the popup editor, you can customize the questions for your popup. Subscriber responses will be saved as custom properties in both Postscript and Klaviyo subscriber profiles.


  1. Under Phone question within the popup editor, you can change the placeholder text.
  2. Under Welcome message, you can craft the message your subscribers will receive once they opt into your SMS program via desktop popup. You can customize this message with photos, gifs, merge tags, coupons, discount links, product links, or a contact card.
  3. Select Add Question to add a question to your popup. Choose if you'd like subscribers to answer this question via freeform text, multiple choice, or by entering a date. Their response will be added to both their subscriber profile in Klaviyo and Postscript under Custom Properties.
  4. Within the first field, craft your question copy (for example: what's your main skin concern? or when is your birthday?). 
    • If adding a multiple choice option, be sure to add the options. You can add up to four.
  5. Under Subscriber property, add the property name you are collecting by either creating a new property or selecting an existing property. You can think of the subscriber property as the main subject of the question (for example: if you ask subscribers what their main skin concern is, the subscriber property would be "skin_concern"). This subscriber property will show up verbatim in the subscriber's Klaviyo profile after they submit the popup form.
  6. Select the Switch Order button to change the order of questions. For compliance reasons, you cannot change the order of your question and phone input field on the Phone collection step. The phone input will always be the second question listed. On the Custom step, you can switch the order of the questions.

What's Next

  • You can send custom properties and emails collected from different Postscript popups to different Klaviyo lists.
  • When a subscriber submits their information via Postscript popup, the custom properties will be forwarded to their email profile in Klaviyo if the integration is set up to forward collected emails to Klaviyo lists.
  • The property name in Klaviyo will be exactly the same as the property name in Postscript.
    • If the property name does not exist on the Klaviyo profile identified by the submitted email, it will be appended to the profile.
    • If the property name already exists on the Klaviyo profile identified by the submitted email, it will overwrite the existing value with the value in the popup submission. 
  • All values are submitted as string/text.
  • Custom properties will be added to the Custom Properties field within the INFORMATION card on a subscriber's Klaviyo profile.

Get Support

Have questions? Please feel free to reach out to our wonderful Support team at or via live chat. You can also submit a support request here!

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