What the feed specification defines
The specification is the document Google publishes describing every attribute a product feed can contain, whether each one is required, and what a valid value looks like. It is the reference your feed is judged against, and every disapproval in Merchant Center traces back to a line in it.
Attributes fall into three groups. Some are required for every product — an identifier, a title, a link, an image, a price, an availability state. Some are conditionally required, meaning they only apply in certain categories or certain countries: clothing needs size and colour, some markets need particular shipping or tax detail. The rest are optional but often decisive, because they give Google information it uses to match your product to a search.
- id — a permanent code that must never be reused for a different product
- title — the text most often matched against a search query
- availability — accepted only as one of Google’s fixed values, not your own wording
- google_product_category — a value taken verbatim from Google’s own taxonomy
Why the feed specification matters
Shopping listings are not written by a copywriter; they are assembled from feed attributes. A missing brand, a vague title or an out-of-date price is not a cosmetic problem — it decides whether the product is eligible at all, and which searches it can appear for.
The specification also changes. Attributes are added, requirements tighten by category and country, and a feed that passed last year can start collecting warnings without anybody editing the shop. Knowing where the rulebook lives is what turns those warnings from a mystery into a task.
Common mistakes with the feed specification
Treating optional as unnecessary is the most expensive habit. Attributes that Google merely recommends are frequently the ones that decide matching, so a technically valid feed can still perform badly.
Format errors come next, and they are dull rather than difficult: a price without its currency code, a date in the wrong pattern, an availability value written in your own words, a category string invented rather than copied from Google’s taxonomy. Each one is rejected silently at item level while the feed as a whole still looks healthy.
Then there is identifier churn. Changing a product’s id because the shop was rebuilt destroys that product’s history and starts it again from nothing. And declaring that no identifier exists, purely to dodge a GTIN requirement on a product that plainly has one, tends to cost visibility rather than save effort.
How to work with it
Read the specification for the countries you actually sell to, not just your own, because conditional requirements differ. Map each required attribute to a real field in your shop before building the export, so nothing is filled in by hand and left to rot.
Write titles for people searching rather than for your internal catalogue — brand, product, key variant — and keep prices and availability flowing automatically from the shop. Then treat the Merchant Center diagnostics as a weekly job, since that is where the specification tells you, in detail, exactly which rule you broke. Ongoing feed management is mostly this: reading those messages and fixing the source.