Delivery options in Shopify Functions input now expose their metafields
Shopify developer change
MerchantDiff detected this entry in Shopify's official developer changelog on September 15, 2026.
This Shopify update is categorized as API, Update, Functions, 2026-10.
What changed
In the Functions cart graph, CartDeliveryOption now includes a metafield field: metafield(namespace: String, key: String!): Metafield The returned Metafield exposes value, type, and jsonValue. Metafields on a delivery option are not persisted after checkout. A delivery option generator function or shipping carrier service response attaches them when it generates the option, and they exist only for that checkout. Access follows the existing metafield ownership rules. A function can read metafields in its own app‑reserved namespace and in any unprefixed shared namespace.
Who is affected
CartDeliveryOption is shared across the Functions cart graph, so this field is available to every Functions API whose input includes cart.deliveryGroups.deliveryOptions. Apps that don’t query this field see no change in behavior. In the legacy Order Discounts and Product Discounts APIs, cart.deliveryGroups is always empty, so the field is present in the schema but never returns a value.
What action may be needed
You don’t need to take any action. Existing functions keep working unchanged on every released API version. If you want to use this field, update your function input queries on API version 2026-10 to request metafield on CartDeliveryOption and handle the returned Metafield values. Related docs Delivery Customization Function API reference for deliveryOptions Metafields for Function input queries Metafield ownership and app-reserved namespaces
Use the official Shopify entry below as the source of truth for technical implementation details, affected APIs, migration instructions and deadlines.
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