# Missing value: item group ID The "Missing value [item_group_id]" issue means variants of one product reached the channel without the shared group ID that ties them together. On Shopify it usually means the feed emits a row per variant but never sends the parent product ID, or builds ids in a way that loses the link between variants. - **Canonical URL:** https://www.feedlab.io/knowledge/errors/missing-value-item-group-id - **Last reviewed:** 3 November 2026 - **Source:** feedlab knowledge base - **Licence:** free to quote and cite with attribution to feedlab ## How this appears in your account - `Missing value [item_group_id]` - `Missing value: item group ID [item_group_id]` - `Missing value: Item group ID` ## Why it happens on Shopify ### The feed sends variants without a parent reference A variant-level feed correctly gives each size and colour its own row and id, but if item_group_id is never mapped, the channel sees unrelated products that happen to look alike rather than variants of one product. ### Variant attributes are present but the group is not Rows that carry color or size and differ only in those values look like variants. Sending the variant attributes without the shared group leaves the channel unable to tell which items belong together. ### The group ID is taken from a field that is sometimes empty Some feeds build item_group_id from a parent SKU, a metafield or a handle-based scheme. Wherever that source is blank, the variants of that product arrive ungrouped. ### Products were split into separate Shopify products per colour Some stores create one Shopify product per colour to get separate pages. Each then has its own product ID, so variants that are really one product are grouped as several, or not at all if each has a single size. ## How to fix it 1. **Use the Shopify product ID as item_group_id** — Every variant of a Shopify product shares one product ID, it never changes and it is always present. That makes it the natural group key, while each variant keeps its own id from the variant ID. 2. **Keep id and item_group_id separate** — The id must be unique per variant and item_group_id must be identical across the variants of one product. Using the same value for both turns grouping into a duplicate id problem. 3. **Send the same variant attributes for every member of a group** — If one variant in a group carries color and size, all of them should. Google flags groups where variants are missing a variant attribute the others have. 4. **Leave single-variant products ungrouped** — A product with only the "Default Title" variant has nothing to group. Sending item_group_id there is harmless, but it is not what fixes the issue. 5. **Decide how to treat colour-split products** — If one product is split across several Shopify products by colour, decide whether they should share a group in the feed. Where they should, a shared metafield or naming convention gives the feed something stable to group on. ## How feedlab handles this feedlab expands every Shopify product into one row per variant, sourcing id from the variant and item_group_id from the parent product, so grouping holds by construction. Where a store groups differently, a rule can override the group key and the preview shows the resulting groups against the real catalogue before the feed is published. ## Frequently asked questions ### When is item_group_id required? Google requires it for product variants: for free listings, and for Shopping ads targeting Brazil, France, Germany, Japan, the United Kingdom and the United States. Products that do not come in variants do not need one. ### What should I use as the item group ID on Shopify? The Shopify product ID. All variants of a product share it, it is always present and it does not change when you rename the product. The value can be up to 50 characters. ### Is item_group_id the same as id? No. Each variant needs its own unique id, while all variants of the same product share one item_group_id. Confusing the two either breaks grouping or creates duplicate ids. ## Primary sources - [Google: item_group_id attribute specification](https://support.google.com/merchants/answer/6324507) - [Google: How to fix missing color for product variants](https://support.google.com/merchants/answer/13318724)