What is Cross-Device Tracking?
By default, GA4 treats each device as a separate user. A customer who browses on their phone and buys on their laptop looks like two different visitors in your reports. This inflates your user count and breaks the customer journey in your analytics.
Cross-device tracking solves this by sending a unique identifier (the Shopify customer ID) to GA4 when a customer is logged in. GA4 uses this to connect sessions from the same person across different devices, giving you a single, accurate view of each customer’s journey.
How It Works
When a logged-in customer triggers any event on your store (add to cart, checkout, purchase, etc.), the app sends their Shopify customer ID to GA4 as a user_id. GA4 then links all sessions with the same user_id together, regardless of which device or browser was used.
This only works for logged-in customers. Anonymous visitors are still tracked by device as usual.
Enabling Cross-Device Tracking
Open the Pasilobus Google Analytics app
Find the Cross-Device Tracking section
Click Enable
Once enabled, all events from logged-in customers will include their user ID.
Verifying in GA4
To confirm cross-device tracking is working:
In GA4, go to Admin > Reporting Identity
Set reporting identity to Blended (recommended) or Observed
Go to Explore > User Explorer to see users identified by their Shopify customer ID
With Blended reporting identity, GA4 uses the user ID to deduplicate users across devices, giving you a more accurate user count.
Requirements
Pro plan required
Customers must be logged in to their account on your store
Works for all events tracked by the app (add to cart, checkout, purchase, etc.)