Storefront API Cart.checkoutUrl now contains key param

API

The Storefront API Cart now returns a new key param appended to CheckoutUrl that is required to render buyer information in checkout. This behavior is applied retroactively to all versions of the Storefront API.

The param is validated and removed as the buyer is navigated into checkout. This change is transparent to the buyer and does not affect what they see in the browser or their ability to copy and share checkout URLs. When a checkout is loaded without the valid key, the cart is cloned, and buyer information is removed.

Example Format: https://example-shop.com/cart/c/c1-09av29f248bb6420de3842b051f6a1a3?key=824bdj25mhg1242bdb385

Action Required: If your app is manually constructing checkout URLs from cart IDs, you need to switch and use cart.checkoutUrl. If you’re augmenting the cart.checkoutUrl with additional parameters, update and validate that your code does not override the parameter and returns a valid destination URL.