Understanding A/B Testing Cookie Retention

A/B Testing Cookie Retention FAQ

Q: What is the cookie retention period when a visitor hits an A/B Test?

A: It depends on the type of test:

  • Theme Tests
    • Shopify sets a cookie called _shopify_essential   that locks a visitor into the theme they preview.
    • Expiry: 1 year from when it’s set.
    • To exit, a user must either delete the cookie or navigate to another theme using a parameter (?preview_theme_id=123   ).

Workaround for breaking the Shopify Theme Test cookie:

    • If you don’t want returning traffic to see a Variant Theme after testing:
      1. Duplicate the Theme (if you want to keep it around), then Delete the original Variant Theme from the test.
      2. Or, if you don’t need the theme, you can just delete it.
    • This ensures that even if the 1-year cookie persists, visitors will no longer be served the Variant Theme.

  • Split URL, Page, and Template Tests
    • Variants are cached for the session.
    • Expiry: 2 hours after inactivity (based on Shopify’s _shopify_s   session cookie).
  • Analytics Cookies
    • Our analytics layer sets a session cookie without a fixed expiry.
    • Expiry: lasts for the browser session (until the window is closed or cookies are cleared).

Q: Do we use our own cookies for A/B test functionality?

A: No, the A/B test behavior relies entirely on Shopify’s cookies.

Q: Where can I find Shopify’s official cookie policies?

A: Shopify Cookie Policy → See section “Reporting and Analytics.”