JavaScript A/B testing on Shopify uses code to alter a storefront experience for an assigned audience when URL, template, or theme tests cannot express the change.
Use code only when needed
Custom JavaScript is useful for interactive behavior, dynamic content, third-party widgets, or narrow DOM changes. Prefer a standard URL, template, or theme test when it can deliver the same hypothesis with less failure risk.
Control timing and flicker
The variant must apply early enough to avoid showing the control first, but it must not block the page longer than necessary. Test slow connections, cached visits, client-side navigation, and delayed third-party scripts.
Defend against theme changes
Selectors and component assumptions can break when a theme is edited. Scope the change, handle missing elements safely, and monitor the experiment after theme releases or app updates.
Provide a clean rollback
Keep the control path independent from variant code and make pause behavior immediate. Remove test-only code after rollout so abandoned experiments do not become permanent storefront debt.
Run the test in Shopify
Sofcy supports URL, template, theme, and custom JavaScript API experiments.
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