The Checkout object in the Storefront API includes the information that's required for a customer to complete checkout and pay for their order.

You can use checkouts to incrementally build and update a draft of the customer's order details before completing the checkout and attempting billing. After a customer's payment is successfully processed, a corresponding order is created in the Shopify admin.

This guide introduces how a checkout works, describes some considerations for payment authentication with 3D Secure, and provides some developer tools and resources that you can use to learn more about building checkouts with the Storefront API.