Meta Ads - Third-Party / Off-Domain Conversion Tracking (Webinars & Events)

When the conversion (e.g. webinar signup, event registration) happens on a third-party platform (Luma, Hopin, etc.) instead of on your website, use this for best-practice setup. Applies to anyone running Meta ads to a webinar or event where signup completes off-domain.

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The Problem

• User lands on your site (e.g. webinar LP with UTM).
• User clicks "Sign up" → goes to third-party platform (e.g. Luma) to complete registration.
• Conversion happens off your domain. If your pixel is only on your site, Meta never sees the signup unless you track it on your domain or on the platform.

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Best Practice: Two Decisions

1. Where to track the conversion (pixel in platform vs thank-you page)

Option	When to use	What to do
Pixel in the platform	Platform supports Meta pixel (e.g. Luma Plus → Calendar → Settings → Options). You have or will get the required plan.	Add your Meta pixel in the platform. Platform sends e.g. CompleteRegistration when user registers. Add the platform's domain (e.g. luma.com, lu.ma) to your Meta pixel Traffic permissions (allow list).
Thank-you page on your site	Platform doesn't support a pixel, or you don't have the plan. Platform can redirect after registration to a URL you control.	Set post-registration redirect to a thank-you page on your domain. Fire Lead or CompleteRegistration on that page. Optimize for that event.

Recommendation: Pixel in the platform is best when available (one setup, real conversion). Thank-you page is the fallback when the platform can't fire the pixel but can redirect.

2. Passing UTM to the signup link

• The platform will not automatically see the UTM from the page the user was on when they clicked "Sign up."
• Best practice: When the user clicks the signup/register button, the link to the third-party site should include the same UTM parameters (e.g. from the current page URL).
• How: Build the signup link dynamically: read the current URL query string (e.g. window.location.search) and append it to the platform's registration URL. Example: https://platform.com/event/xyz → https://platform.com/event/xyz?utm_source=linkedin&utm_medium=paid-social&utm_campaign=...
• Ensures attribution and platform-side reporting stay correct.

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Example: Luma

• Pixel: Luma Plus → Calendar → Settings → Options → Meta Tracking Pixel. Luma sends PageView, CompleteRegistration (free events), Purchase (paid). Add luma.com (and lu.ma if used) to Meta pixel Traffic permissions.
• UTM: Pass UTMs from the webinar LP into the Luma registration URL when the user clicks signup (e.g. via JS appending current URL params to the Luma link).

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Quick Message Template

Use when asking someone to enable pixel + UTM pass-through on their side:

Short version:

Hi [Name],

Quick ask for [webinar/event name] so we can track signups properly in Meta:

1. Meta pixel in [platform] - If you're on [platform plan that includes pixel, e.g. Luma Plus], can you add our Meta pixel in [platform]? ([Where to find it, e.g. Calendar → Settings → Options].) That way we get real "registration" events and can optimize for signups. We'll allow [platform domain] in our Meta pixel settings on our side.

2. UTM on the signup link - When someone clicks "Sign up" on the [webinar/event] page, we need the same UTM params (from the page they're on) to be passed through to the [platform] registration URL. That keeps attribution correct. If your team can update the signup button/link to append the current URL's UTM parameters to the [platform] link, we're set.

Thanks, [Your name]

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Related Files

• meta-setup-and-tracking.md - Pixel setup, Traffic permissions (allow list), conversion events
• meta-capi-and-events.md - CAPI, event hierarchy, HubSpot vs n8n
• campaign-structure.md - How tracking fits into overall campaign architecture