Item group ID
An item group ID is the Google Merchant Center attribute that ties the sizes and colours of one product together, with one value on every variant.
- item_group_id
What it means
In a Google Merchant Center feed, each size and colour of a product is sent as a product of its own, with its own ID. The item group ID is the value they share. Google’s example is a T-shirt in three sizes and three colours, sent as “a total of nine separate products” with one item group ID.1
The value can be 1 to 50 characters. Google’s best practice is to use the parent SKU, but “Don’t submit a parent SKU as a separate product.” Once assigned, the value should not change. Case does not tell two values apart either: ‘abc123’ and ‘ABC123’ are “interpreted as the same product”.1
It is required for free listings of variants, and for Shopping ads on variants in six countries, the UK among them.1
Think of it like this
It works like the address of a block of flats. Each flat has its own number, and the street address they share shows they are all in one building.
For example
A supplier sends a hoodie in three colours as HD-200, HD-200-BLK and HD200-GRY, with nothing linking them. Rebuilt for Google, each colour and size becomes a row with its own ID, such as HD-200-NVY-M. Every row carries the item group ID HD-200.
Why it matters
Without it, Google has no way to show a product’s sizes and colours “as a group, instead of separately”. It is required for variants in the UK, and Google says it will disapprove products that miss its minimum requirements for the attribute, one of which is a single value shared by every variant of the same product.1
Not to be confused with
The item group ID is a different thing from the ID. Google’s rule is to “Use the ID attribute to uniquely identify a single product”. The item group ID ties several products together as variants.1
Sources
- Google Merchant Center Help. Item group ID [item_group_id].