In the Summer '25 release, our product team has optimised the checkout process to enhance efficiency in DML operations for order creation.
As a result: CartCheckoutSession.OrderId will not be available for triggers or flows until the Order Summary record is committed to the database.
ACTION REQUIRED: Update Your Existing Automations.
If you have Apex triggers, Flows, or other automations that operate on Order Summary creation:
CheckoutSession.OrderId to retrieve cart information after the Order Summary process has begun.OrderSummary.ExternalReferenceIdentifier field.CheckoutPlaceOrder_<cartId>_<orderReferenceNumber> This format directly links the Cart and Order Reference Number.<cartId> and <orderReferenceNumber> from this string. For example, in Apex, you can use String.split('_') and access the parts by their index.Note for High-Scale Order Ingestion (HSOI): For orgs with HSOI enabled, the CheckoutSession.OrderId (on Cart) and related direct OrderReferenceNumber fields (on OrderSummary or associated objects, if previously populated this way) will not be populated. Parsing OrderSummary.ExternalReferenceIdentifier is the only method to retrieve the cartId in these scenarios.
To improve efficiency, use the OrderSummary.ExternalReferenceIdentifier field, which already contains both the Cart ID and Order Reference Number.
CheckoutPlaceOrder_<cartId>_<orderReferenceNumber>004811112

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