productVariantUpdate not update the quantity of my variant

Topic summary

Issue: Updating a variant’s inventory via GraphQL using productVariantUpdate doesn’t change quantity. Using productUpdate risks deleting unspecified variants.

Key guidance:

  • productVariantUpdate cannot update inventory. Use GraphQL inventoryQuantityAdjust to change available by a delta. Example provided using inventoryLevelId (the location-specific inventory level) and availableDelta (increment/decrement).
  • For absolute quantity (set, not adjust), support pointed to REST Admin inventory_levels endpoints: set.json (set exact available) and adjust.json (delta). Doc link shared for REST.
  • To update variant fields without deleting others, use productVariantsBulkUpdate. It’s implied for non-inventory fields (e.g., price), not quantities.

Open questions/clarifications:

  • Request for GraphQL inventoryQuantitySet doc: not found; no GraphQL mutation confirmed for setting “available” directly. Support pivoted to REST for that use case.
  • Whether productVariantsBulkUpdate can update quantities remains unanswered.
  • A participant notes confusing behavior: productVariantUpdate accepts inventoryQuantities input but doesn’t change stock and doesn’t error; asks for rationale and better error/warnings.

Status: Partially resolved. Clear path: use inventoryQuantityAdjust (GraphQL) for deltas or REST set/adjust for absolute updates. Some GraphQL-specific needs remain unresolved.

Summarized with AI on January 20. AI used: gpt-5.

Thanks @Liam ,
what is the best way to update product quantities by having the id of the product, variant and inventoryItem ?
I am passed the total quantity in the inventory so the delta would require calculations that I would rather not do .
Thank you very much for your support