Item ID

An item ID lets a system distinguish one product record from another and recognize it when new data arrives. In Google Merchant Center, you submit it through the id attribute. Google recommends using a product’s SKU when appropriate.

Choose the value deliberately. A title may change as you improve product copy. The identifier should remain attached to the same product.

Keep the identity stable

Google uses the ID to connect a product with its information and performance history. Changing it disrupts that continuity. Avoid generating a new value on every export or attaching a campaign name to an otherwise stable ID.

Each different product needs its own value. Do not recycle an old ID for a new product, or rely on uppercase and lowercase letters alone to distinguish two items.

Stable IDs also support data joins. In Merchant Center, supplemental data must match the product ID in the primary source. A mismatch prevents the intended records from lining up.

Example

Imagine a retailer selling the same backpack in navy and red. It assigns fictional item IDs PACK-NAVY and PACK-RED. Each record carries the price, image, and availability for that color.

Both records can share an item_group_id, such as PACK, to show that they are variants of one product. Their individual IDs remain different. The group identifier describes the relationship between them.

If the navy backpack sells out and later returns, the retailer keeps PACK-NAVY for that same variant. It does not give the identifier to a different backpack during the gap.

Check the exact item being identified

An ID identifies the record you submit. A GTIN identifies a trade item across businesses. An item group ID connects variants. Keep these roles separate when mapping your catalog.

Before changing an existing ID scheme, check every system that uses those values. A renamed spreadsheet column is straightforward; changing the identifiers inside it changes how records are matched.