Schema Markup
Schema markup is structured vocabulary from schema.org that you add to a web page to label its content for machines, telling search engines and AI systems exactly what each element means so they can render rich results and recognise the page as a specific entity.
Plain HTML tells a browser how to display text, but it does not say whether a number is a price, a rating, or a phone number. Schema markup closes that gap by tagging content with agreed types and properties, usually written as JSON-LD in a script tag. For a store, the types that earn the most are Product, Offer, Review, AggregateRating, Organization, BreadcrumbList, and FAQPage, each one mapping a piece of the page to a meaning a machine can act on.
The payoff is eligibility for rich results (star ratings, prices, and FAQ accordions in the search listing) and clearer entity recognition, which increasingly feeds AI answer engines that cite sources rather than rank links. Markup does not guarantee a rich result; it makes the page eligible, and the search engine still decides whether to show one.
The rule that trips people up is the visible-content match: the markup must describe content a user can actually see on the page. Marking up reviews or ratings that are not present, or inflating numbers, is against Google guidelines and can trigger a structured-data manual action. Add the vocabulary to reflect what is already there, then validate it with the Rich Results Test before shipping.