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Meta Pixel — Lead Event

Meta Pixel — Lead Event

Fires a Meta Pixel Lead event with custom parameters sourced from GTM variables. Distributed via CDN so updates push automatically.

What it does

  1. Reads payload values from GTM variables (traffic source, page path, optional form name)
  2. Strips empty/missing values so unset variables don't pollute the event
  3. Calls fbq('track', 'Lead', payload)

Prerequisites

  • The base Meta Pixel tag (meta/pixel/base/) must be installed and firing on All Pages — Page View. Without it, fbq is undefined and this tag warns and exits.
  • A GTM variable named cJS - Traffic Source returning last-touch traffic source (Custom JavaScript variable).
  • A GTM variable named cJS - Ad Placement returning the ad placement (Custom JavaScript variable).
  • Built-in GTM variable Page Path enabled.
  • (Optional) A Lookup Table variable named LUT - Convert Form ID to Text mapping form IDs to human-readable form names — uncomment the line in lead-config.html to send it.

Installation

Step 1: Create the Custom HTML tag

In GTM, go to Tags → New:

  1. Click Tag Configuration → choose Custom HTML
  2. Paste the contents of lead-config.html into the HTML field
  3. (Optional) Uncomment the form_name line if you have the LUT - Convert Form ID to Text variable set up
  4. Click Triggering → choose your form-success trigger (e.g., Custom Event - GF Form Success from the Gravity Forms listener, or any other trigger that signals a lead)
  5. Name the tag: cHTML - Meta Pixel Lead
  6. Save

Step 2: Preview and publish

  1. Click Preview to test in Tag Assistant
  2. Submit a form on your site — verify the Lead event fires by:
    • Checking the Network tab in DevTools for a request to facebook.com/tr with ev=Lead
    • Using the Meta Pixel Helper Chrome extension (should show a Lead event with your custom parameters)
  3. Once verified, publish your container

Payload structure

The event is sent with the following parameters:

ParameterSourceNotes
lead_typeHardcoded Form SubmitCustom param — change in lead-config.html if this tag fires for a different lead type (e.g., Phone Call)
traffic_source{{cJS - Traffic Source}}Custom param — last-touch traffic source
content_name{{Page Path}}Meta standard param — page where the lead occurred
ad_placement{{cJS - Ad Placement}}Custom param — ad placement
form_name{{LUT - Convert Form ID to Text}}(Optional) Custom param — human-readable form name

Empty values are stripped before sending.

How updates work

The event logic is hosted on jsDelivr and currently pulled from @main for testing. Once a v1.x.x git tag is published, switch the src in lead-config.html from @main to @v1 for cache-stable releases.

Known limitations

  • One lead type per tag: lead_type is hardcoded in the cHTML loader. Duplicate the tag for different lead types (Phone Call, Demo Request, etc.) and edit the value.
  • No event deduplication: If both the browser pixel and a server-side CAPI integration send Lead events, you'll need to add an event_id to dedupe. Not handled here.
  • No consent mode integration: Handle in your CMP separately.

Disclaimer

This script packages Meta's standard Pixel snippet for distribution via the Marketing Toolkit. The underlying Pixel code is provided by Meta Platforms, Inc. and subject to their terms.

Provided as-is under the MIT License. Test thoroughly before relying on it for revenue attribution.

Packaged by W.H. Boggs — whboggs.com → Free Meta Ads audit

The code

chtml-lead-config.html
html
<script>
  // Note: Requires cJS - Traffic Source and cJS - Ad Placement.
  // Delete these lines if you do not want to add these parameters.
fbq('track', 'Lead', {
  lead_type: 'Form Submit', // Define Lead Type
  traffic_source: '{{cJS - Traffic Source}}', // Finds Last Touch traffic source
  content_name: '{{Page Path}}', // Finds page path
  ad_placement: '{{cJS - Ad Placement}}' // Finds ad placement
});
</script>