Currently it is not possible to specify customAttributes (line item properties) for a line item, when we try to add variant / custom item to an existing order (orderEdit API : orderEditAddVariant - GraphQL Admin and orderEditAddVariant - GraphQL Admin).
I would like to request the ability to specify customAttributes (line item properties) when adding variant or custom item during order edit.
Hope this request can be considered, thank you
Hey again @soulchild 
- hope all’s well! Thanks for flagging this. This is a pretty desired feature that we have on our radar (there’s a pretty interesting discussion here from a while back in our old forums if you’d like to take a look at it).
In that thread one of the recommendations is to leverage metafields (more info here). There isn’t a specific line item metafield type, but you could use Order metafields to store the data needed (using the orderUpdate mutation).
Not the most ideal workaround for sure - but metafields are pretty robust and are the recommended method at the moment.
I’ll link to your thread in my notes here for the feature request record we have on our end though, just so we track it on our side - hope this helps!
Hi Alan,
Thank you for the reply. Unfortunately the workaround of using Order metafields does not work, as we can’t show order metafields on order confirmation / update email template (https://help.shopify.com/en/manual/fulfillment/setup/notifications/email-variables#order-fulfillment), as we have to convery the information of the line items to customers.
Thank you for linking the feature request!