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Use the GTAG GET API template in Google Tag Manager to surface the GA4 session ID in your data layer, then capture it with the Invoca Tag.

Applies to

  • Customers using Invoca’s Google Analytics 4 integration
  • Customers integrated with multiple Google Analytics properties
  • Customers using Google Tag Manager to manage their GA4 tags

Objective

Capture attribution for the Google Analytics session ID.

Steps

  1. In Google Tag Manager, go to Templates, search for GTAG GET API in the template gallery, and click Add to workspace.
  2. Go to Tags and create a new tag using the GTAG GET API template.
  3. Set your GA4 Measurement ID in the appropriate field.
  4. Check the box next to Session ID under Default Fields to Get.
  5. Add this tag to a tag sequence so it fires after your GA4 Configuration tag (or Event tag, if you’re not using a Configuration tag): open your Google Analytics 4: Configuration tag, go to Advanced Settings > Tag Sequencing, check “Fire a tag after … fires,” and select the tag you just created.
  6. In Preview mode, confirm you see a new Data Layer event named gtagApiGet. If you don’t, either there’s no GA4 configuration on the page, or the API tag fired before gtag() had time to load.
  7. Create a Marketing Data field:
    • Type: Short Text
    • Partner (API) Name: ga_session_id
    • Friendly Name: Google Analytics Session ID
    • Attribution Model: Last Touch
  8. Update your Invoca Tag to capture the session ID:
    • Click the gear icon, then Invoca Tags, and find the Tag for the site with the GA4 property you’re integrating.
    • Open the Revision History tab and create a new draft (or continue an existing one).
    • Find the Google Analytics Session ID parameter in the Marketing Data section.
    • Set Data Source Type to JavaScript Data Layer, and paste the session ID variable name as the Data Source Name.
  9. Test that the session ID attribution is being captured as expected before publishing your draft.

Where to go next

Last modified on September 25, 2026