Experiment Engine
Test a new theme before you publish it
Compare your live theme with up to four unpublished themes before you publish one. We never change a theme; publishing the winner is your step in Shopify admin.
A Full theme test compares your live (published) theme, the original, with one to four unpublished themes of your store. Add the theme in Online Store, Themes first. The test never edits a theme.
- Each version picks one unpublished theme. Themes made by the Shopify CLI for development are not offered: they expire and can't take real traffic.
- Shoppers in a version are sent to the same page with their theme previewed and Shopify's preview bar hidden. Query parameters and UTM tags are kept, a page already showing a preview is not redirected again, and cart, checkout and account pages are left alone.
- The page can be hidden for up to 300 ms while it switches. The address and canonical tag stay the same, so search engines keep indexing your live theme.
Before you launch
- Turn the Experiment Engine app embed on in each tested theme (theme editor, App embeds), and in your live theme. Launch checks it; without it visits to that theme are not counted.
- Don't edit the tested themes, or your live theme, while the test runs. A change in one but not the other makes the results unreliable.
- Preview each version and check add to cart and checkout in it.
While it runs
The Results tab checks the tested themes every time you open it. If a tested theme was published, deleted or turned into a development theme, or its app embed went off, the Themes health pill turns red. A paused test can't be resumed until you fix it.
Ship the winner
- On the Results tab, select End test and choose the winning theme.
- The test ends and every shopper sees your live theme again. Nothing is changed in your store.
- Select Open Themes in Shopify admin, find the winning theme and choose Publish.