How to Set Up Cross-Site Testing

This guide walks through the one-time setup required to enable Cross-Site Testing in PDQ.

January 25, 2026

Table of contents

• Before You Start
• Step 1. Open the Cross-Site Test Creator
• Step 2. Copy the Cross-Site A/B Test Script
• Step 3. Go to Shopify Admin
• Step 4. Open the Theme Code
• Step 5. Open theme.liquid
• Step 6. Paste the Script
• Step 7. Save the File
• Important Notes

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.