Klaviyo Form GTM Event Listener

Track Klaviyo email signup form submissions in Google Tag Manager. Capture formId, formTitle, and formEmail and fire GA4 events on klaviyoFormSubmission.

klaviyoemail-marketingecommerceformsgtmga4

Event fired

klaviyoFormSubmission

Key variable

formId

Klaviyo

Overview

Klaviyo is an email marketing and SMS platform used primarily by eCommerce stores. Its forms, pop-ups, flyouts, embedded, dispatch klaviyoForms events. This listener intercepts those events and pushes submission data to the GTM dataLayer.

Event fired: klaviyoFormSubmission Variables: formId, formTitle, formEmail Credit: Julius Fedorovicius (email field added by DumbData)

Why Use This Listener

Klaviyo's forms are critical lead capture and email list growth tools. Without this listener, you cannot:

Track email sign-ups as GA4 conversions
Fire Meta's Lead event on Klaviyo sign-up
Know which Klaviyo form (pop-up vs. embedded) converts better
Capture the email address for enhanced conversions

Common Use Cases

Track newsletter and discount email sign-ups as GA4 conversions
Fire Lead event to Meta on Klaviyo form submission
Measure pop-up vs. embedded form conversion rates
Use sign-up events to build Google Ads RLSA audiences
Send hashed email to Google for Enhanced Conversions
Connect Klaviyo sign-ups to purchase data in GA4

How It Works

Klaviyo dispatches a custom event named klaviyoForms on the window. The listener filters for submit event types and pushes the form ID, title, and email to the dataLayer.

Installation

html

<!-- GTM Custom HTML Tag: Klaviyo Form Listener -->
<script>
window.addEventListener('klaviyoForms', function(e) {
  if (e.detail.type === 'submit') {
    window.dataLayer = window.dataLayer || [];
    window.dataLayer.push({
      'event': 'klaviyoFormSubmission',
      'formId': e.detail.formId,
      'formTitle': e.detail.metaData.$source,
      'formEmail': e.detail.metaData.$email
    });
  }
});
</script>

Fire on: All Pages (Pageview).

Data Layer Output

json

{
  "event": "klaviyoFormSubmission",
  "formId": "RaMkJd",
  "formTitle": "Summer Sale Popup",
  "formEmail": "customer@example.com"
}

Trigger Configuration

Trigger Type: Custom Event
Event Name: klaviyoFormSubmission

Variables to Capture

Variable Name	DL Key	Example
DLV – Klaviyo Form ID	`formId`	`"RaMkJd"`
DLV – Klaviyo Form Title	`formTitle`	`"Summer Sale Popup"`
DLV – Klaviyo Email	`formEmail`	`"user@example.com"`

GA4 Mapping Recommendations

GA4 Event	Parameter	Value
`sign_up`	`method`	`"klaviyo"`
`sign_up`	`form_id`	DLV – Klaviyo Form ID
`sign_up`	`form_name`	DLV – Klaviyo Form Title
`sign_up`	`email`	DLV – Klaviyo Email (hashed for Enhanced Conversions)

Debugging

Problem	Cause	Fix
Event not firing	`klaviyoForms` event not dispatched	Confirm Klaviyo script is loading
`formEmail` is empty	Email field not named email	Check Klaviyo form field name mapping
Fires on open, not submit	Missing `type === 'submit'` filter	Add the filter check

Best Practices

Use sign_up not generate_lead for email subscriptions, better GA4 taxonomy alignment
Hash the email before pushing to dataLayer if using Enhanced Conversions
Capture formTitle, it makes GA4 reports more readable than raw form IDs
Create per-form-type events, popup sign-ups vs. embedded sign-ups have different intent signals

Performance Considerations

One window.addEventListener call, zero performance impact
The klaviyoForms event fires asynchronously after Klaviyo processes the submission

Related Listeners

More Forms

Cognito Form

Contact Form 7

cf7submission

ConvertKit

converkitform.submit

← All Forms GTM Cookbook →