Overview

Checkout flow, request payload essentials, redirect behavior, and common capabilities.

The Checkout API starts the ESW hosted checkout flow.

Retailers send cart data, shopper context, and checkout configuration to ESW. Older integrations may refer to this as the Preorder API.

What it does

When ESW receives a valid checkout request, it returns a unique redirect URL.

The shopper opens that URL and completes checkout in the ESW UI. They can review the order, choose delivery, and enter shipping, billing, and payment details.

After payment succeeds, ESW completes checkout and the order moves into post-checkout processing.

Typical flows

The checkout session starts the same way in both sync and async flows. The difference is what happens after payment succeeds.

Synchronous

1. The shopper clicks Checkout on the retailer site.
2. The retailer sends the checkout payload to ESW.
3. ESW returns a redirect URL.
4. The shopper completes checkout in the ESW UI.
5. ESW sends the order confirmation webhook to the retailer.
6. The retailer returns approval and can send its own order number.
7. The shopper sees the confirmation page after processing completes.

Asynchronous

In both flows, the retailer can send its own order number during order confirmation. If no order number is returned, ESW uses the retailerCartId.

For the post-payment confirmation step, see API Method

What you send

A typical checkout request includes:

• A unique cart reference
• Line items, quantities, and product identifiers
• Pricing and currency data
• Delivery country
• Shopper language and localization data
• Product display data such as title, image, color, and size
• Retailer checkout settings and optional metadata

Common capabilities