SellingPlan metafields are now available in the Admin and Storefront API

As of 2024-07 version, SellingPlan resources support metafields. Use metafields APIs to store additional information in metafield values.

You can use the sellingPlanGroupCreate mutation and sellingPlanGroupUpdate mutation to update and create metafields on the selling plan objects by specifiying the metafields field of sellingPlanInput.

To learn more about metafields, refer to the metafields documentation.