How the Amazon Catalogue Works: ASINs, Contributions and Who Controls a Listing

The word listing suggests something a seller owns, like a classified advertisement. On Amazon a listing is a page in a catalogue, one page per product, and every seller who offers the product contributes to it. The title a seller wrote can be replaced by another seller's, or by Amazon's own systems, and the seller who wrote it finds out when the page changes. Most catalogue confusion, and most of the support cases about it, comes from that one fact.

This is how the catalogue works: what an ASIN is, how a page is built from contributions, why a new offer lands on an existing page, how the brand owner comes to control the page, and what to do when it is wrong.

Amazon's catalogue rule is that each product has exactly one page, identified by an ASIN, and every seller of that product sells on that page. A seller creating a listing for a product that already exists is not creating a page; the catalogue matches the product identifier, the GTIN or UPC on the barcode, to the existing ASIN and adds the seller's offer to it. Creating a second page for the same product is a duplicate listing, which Amazon merges or removes, and the seller who created it loses the work. The adding keywords article assumes the page is yours to edit; this article is about when it is not.

The identifier is what makes the match, which is why a product without one, or with one that belongs to something else, causes trouble: a wrong GTIN attaches a seller's offer to somebody else's product page, and the customer receives the wrong thing.

Every seller on an ASIN can submit values for its attributes: the title, the bullets, the description, the images, the brand, the dimensions. Amazon stores all of them as contributions and shows, for each attribute, the one it trusts most. Trust is decided by rules rather than by who was first: a brand owner's contribution outranks a reseller's; a contribution that matches the manufacturer's data outranks one that does not; a contribution flagged by customers loses; and Amazon's own systems, which fill attributes from the manufacturer or from images, can outrank everybody where a field is empty or contested.

That is why a title changes under a seller. Another seller contributed a different title, or Amazon's systems did, and the contribution won. The seller's own contribution is still stored; it is simply not the one shown. A seller who edits the title back is contributing again, and if nothing has changed in the trust order, the edit loses again, silently.

Brand Registry is the mechanism. A brand enrolled in Brand Registry, with the selling account listed as its owner or an authorised representative, has its contributions to its own products' pages given the highest trust. In practice the brand owner's title, bullets, images and A+ content hold, and a reseller's contributions do not displace them. The brand owner can also report a listing that misrepresents the product, and can restrict who may sell on its ASINs at all.

For a brand that is not enrolled, every seller on its pages is an equal contributor and the page is whatever the trust rules produce that week. That is the most common reason a manufacturer's own listing carries a reseller's photograph of the product in its packaging. The enrolment is the work of our Brand Registry service for the brands we run, and what a reseller may do on a brand's page at all is the subject of the reselling article.

First find out whose contribution is showing. The listing's attributes in Seller Central show what the account contributed; the live page shows what won; the difference is the contested attribute. For a brand owner, the fix is to confirm the Brand Registry role on the account and submit the correct value again, which then holds. For a reseller on a brand's page, the fix is a case to Seller Support with evidence, the manufacturer's own data or images, because a reseller cannot outrank the brand and Amazon's systems by contributing harder.

For an attribute Amazon's own systems changed, the case is the same, and it is the slowest kind. The Seller Support cases article is how to write it so it is read. What never works is deleting the offer and recreating it, which changes nothing about the page and resets the seller's history on it.

The catalogue is built the way it is so that a customer searching for a product finds one page with every offer on it, and the rules that frustrate sellers are the rules that make that true. A seller who works with it registers the brand, uses the right identifiers, contributes complete and accurate data, and reads the live page rather than the edit form. A seller who works against it creates duplicates, fights the trust order by re-editing, and files cases that ask Amazon to prefer a contribution over its rules.

For the brands we run, the catalogue is checked monthly: the live page against the account's contributions, attribute by attribute, and any difference traced to its contributor. It is dull work and it is the difference between a page a brand controls and a page it visits.