Product markup is structured data that identifies an item for sale and describes key attributes in a machine-readable format. It can include a product name, brand, model or other identifiers, as well as commercial details supplied through related offer data, such as price and availability. Shipping and return information may also be represented with dedicated fields.
Search engines and shopping tools can use this data to interpret product pages, but markup does not guarantee that a product will appear in a particular result or assistant. In practice, merchants publish it on product pages or in feeds, and automated systems parse it to compare or display offers. Incomplete, stale, or inconsistent fields can mislead those systems. Defenses include validating markup, keeping it synchronized with live inventory and prices, and restricting access to systems that publish catalog data.