Is this Shopify + GTM + Meta first-click tracking setup possible?

Facebook Conversion API
1

I have a Shopify store and want to implement first click attribution for Facebook ads.

  • Suppose If we Capture the first ad click using fbclid and or UTM parameters on the user first session.

    When the customer finally purchases, can i fire a custom Meta event like Purchase_FC on Events manager.

    After this purchase_fc events fire. Also send the same event via Meta Conversions API (CAPI) with proper deduplication using the same Event ID for browser + server events.

    If after click the ads, Suppose user did not purchase anything, and come back after 5 days later. He purchase the product. So we can able to attribute this kind of events in campaign.

I m using Google Tag Manager, so my questions are:

  1. Is this type of first-click Meta attribution tracking possible with Shopify + GTM?

  2. What is the best way to store the first-touch source?

  3. What is the best setup for sending the same Purchase_FC event to Meta Pixel + CAPI with deduplication?

    In Meta Ads Manager, can this be used to report something like FCROAS or Purchase FC through a custom custom columnfor external reporting?

If anyone has work this kind of situation before. How to setup this

Waiting for a positive response. Thank you

2

Hi,
Yes, this is possible using Shopify and GTM. Typically, this requires capturing the source of the first interaction (fbclid, UTM parameters, referrer, etc.) and storing it in a persistent first-party cookie or in localStorage without overwriting it on subsequent visits.
When a purchase is made, the stored values are retrieved, and a custom Purchase_FC event is sent via both the Meta Pixel and the Conversions API using the same event_id for deduplication.
However, keep in mind that Meta Ads Manager will not use your custom Purchase_FC event for its attribution model or optimization. If you want to calculate FCROAS, you’ll need to build those reports externally (for example, in BigQuery or Looker Studio).
You can also include custom parameters with the event. If Meta supports your intended use case, you may be able to build specific logic around them. However, it’s generally better to implement a separate attribution model tailored to your reporting requirements.