How to Set Up Cross-Domain Split Testing
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Most A/B testing tools only let you test pages on one domain. If your business spans multiple platforms, that is a serious limitation.
Maybe you want to test your current WordPress landing page against a version built in Lovable or Astro. Maybe you want to split traffic between your WordPress site and a Shopify checkout. Maybe you are moving to a new platform entirely and want to test it against the old one before you commit.
What cross-domain split testing actually does
It is simpler than it sounds. Instead of both variations living on your WordPress site, your variations can live on completely different domains.
Variation A could be a page on your WordPress site. Variation B could be a page on Shopify, a Lovable build, an Astro site, or any external URL you want to test. AB Split Test splits traffic between them and tracks results in your WordPress dashboard, exactly the same as any other test.
How to set it up
Step 1: Add your external domain
Go to AB Split Test > Settings > Tracking & Privacy. Scroll down to the External Domain Testing section. Add the domain of your external site and save. AB Split Test will generate a tracking script for that domain.
Step 2: Add the script to your external site
Copy the generated script and paste it into the header of your external site. Most platforms have a custom code or header script section where you can do this. Save and you are done on the external site.
Step 3: Create your test
Back in AB Split Test, create your test. A full page test takes an external URL as a variation. Code (CSS), on-page and point-and-click Magic tests run on external pages too: switch on Also run on external domains, or launch the Magic editor straight onto the external page from your domain list.
That is the entire setup. No developer needed.
Which conversion goals work across domains
Page visits, element clicks, link clicks, time active, scroll depth, URL conversions, text appearing on the page, HubSpot form submissions and JavaScript conversions all work on external domains.
Goals that run inside WordPress do not: WooCommerce, Easy Digital Downloads, WordPress form plugins, server-side PHP or AJAX actions, and block or module triggers. For a form the script cannot see, push to window.abConvert from your form's own success callback.
Revenue tracking is not WordPress-only. The script reads the order total from the thank-you page on its own - known URL parameters, common order-total markup, or the visible "Order total" line - and window.abst.abConversionValue sets it exactly where a checkout is unusual. Order Value Optimization therefore works on Shopify, SureCart, FluentCart or a custom checkout.
Optional: CDN integration
If your external site runs on Cloudflare or Bunny CDN, you can connect it inside the settings by entering your hostname and API key. This keeps cache clearing automatic whenever a variation updates so visitors always see the right version.
It is optional. The test works without it.
What this is not
This is different from the Fingerprint Pixel feature already in AB Split Test.
The Fingerprint Pixel tracks conversions on an external domain. You run a test on your WordPress site and record when someone converts on an external page.
Cross-domain split testing goes further. The variations themselves live on different domains. You are splitting traffic between completely different URLs on completely different platforms and comparing them head to head.
Both features have their place. If your test lives entirely on WordPress and you just need to track a conversion that happens elsewhere, use the Fingerprint Pixel. If you want to test two completely different pages on two completely different domains, this is the feature you need.
Who this is for
This is most useful if you are:
- Testing your current site against a rebuild on a new platform before you migrate
- Running a WordPress landing page that sends traffic to an external checkout or funnel
- An agency testing different page builder outputs against each other across domains
- Anyone whose conversion journey crosses more than one domain
Getting started
Cross-domain split testing is available on the paid Teams plan. Full setup instructions are in the documentation.
If you are not yet on a paid plan, start a free trial at absplittest.com/free.