Shopify integration - Knit

On a standard Shopify Liquid theme, Knit uses three pieces:

Piece	Role
Theme app extension	Renders the bundle widget on matching product pages
Cart line-item properties	Carries `__FB_ATC_UID` so lines stay grouped
Discount Function	Applies the bundle reward at checkout

Enable the Knit app embed in the theme editor so the widget can mount. You do not need the theme app extension for headless endpoints or Tapcart. Those load from the Knit app origin:

https://app.knit-bundle.co

Add to cart override

If a bundle has ATC override enabled, the shopper clicks the theme’s Add to Cart button and Knit adds the bundle lines instead of a single product. The widget should not show its own add-to-cart button in that mode. If override is off, the widget shows its own add-to-cart control.

Checkout

The discount still comes from the Knit automatic discount in Shopify admin → Discounts. Details: How discounts apply.

⌘I