Cross-Site Testing lets you split traffic between full Shopify themes and route each theme to a matching checkout experience, ensuring storefront messaging and checkout behavior stay aligned.
Before You Start
Cross-Site Testing requires:
At least two Shopify themes
PDQ installed and active
Checkout groups already configured in PDQ
The setup is done once per theme.
Step 1. Open the Cross-Site Test Creator
In PDQ, create a new Cross-Site Test.
Complete the Details and Traffic Allocation steps first.
Proceed to the Installation tab.
Step 2. Copy the Cross-Site A/B Test Script
In the Installation tab, locate the Cross-Site A/B test script.
Copy the full script.
Step 3. Go to Shopify Admin
Navigate to:
Online Store. Themes.
You will repeat the next steps for each theme included in the test.
Step 4. Open the Theme Code
For the theme you want to test, click Edit code.
Step 5. Open theme.liquid
In the left sidebar, open:
Layout. theme.liquid.
Step 6. Paste the Script
Paste the script immediately after the opening tag.
Do not modify the script.
Step 7. Save the File
Click Save to apply the changes.
Repeat Steps 4–7 for every theme in the test.
Important Notes
This is a one-time setup per theme. You do not need to repeat it for future tests.
Once installation is complete, the test is created as a Draft.
You can start the test at any time from the Drafts view.
Cross-Site Testing is now active and ready to run.