Update shopify product Weight based on product tag using flow

Shopify Plus

Topic summary

Goal: Automatically set a product’s weight at creation in Shopify Flow based on a product tag.

Initial approach: Poster planned to use “Update product metafield” and asked for the correct namespace/key, type, and value format for Shopify’s weight field.

Key guidance (latest): Weight should not be stored as a metafield. Instead, update the inventory item’s native weight fields (inventoryItem.measurement.weight) via the Admin GraphQL API. In Flow, use the “Send Admin API request” action to call the inventoryItemUpdate mutation.

Context/terms:

  • InventoryItem: The object tied to a product variant where physical measurements (like weight) are managed.
  • Admin GraphQL API: Shopify’s API used to mutate inventoryItem fields.

Outcome/status: A clear implementation direction is provided (use inventoryItemUpdate via Flow). No example payload or confirmation of success yet; discussion appears open pending implementation details or validation.

Summarized with AI on December 16. AI used: gpt-5.
1

I would like to automatically populate a product’s weight using flow upon product creation. I can use a specific tag to determine the correct value. Is there a way to achieve this in flow?

I assume the action would be to ‘update product metafield’ but to do this I need the namesake and key (and know the correct ‘type’ of metafield) for the shopify weight field and understand how to format what goes into the ‘Value’ field of the action.

Can someone help?

2

Hi @SAnderson_GW :waving_hand: While you could define weight as a metafield, the most appropriate way is to update the inventoryItem.measurement.weight fields. You may be able to automate that in Flow using an inventoryItemUpdate mutation via the Send Admin API request action.