Mirrors Admin GraphQL productVariantsBulkUpdate — the counterpart to the POST on this path, which only CREATES. This is the ONLY way to change a price, SKU, barcode or compare-at price after creation (products/variant-cost writes COGS and nothing else).

Body: { variants: ProductVariantsBulkInput[], allowPartialUpdates?: boolean }. Every entry MUST carry the variant's own id — there is nothing else to match on. SKU lives under inventoryItem.sku, not a top-level field.

allowPartialUpdates defaults to Shopify's false: one invalid variant rejects the whole batch. Pass true to apply the valid ones and read the rest from userErrors.

• Write — changes a live store immediately; needs a write-scoped token.