Schema.org

Schema.org is a standardized structured data vocabulary — developed jointly by Google, Microsoft, Yahoo and Yandex — used to describe the content of a page unambiguously in a form search engines can read. Instead of guessing that a fragment is a price, a rating or an event date, the crawler reads it directly from the attached markup, and can then present the content in a richer way.

How Schema.org works

Schema.org defines a hierarchy of types (for example Product, Article, Recipe, LocalBusiness, Event, FAQPage) and the properties that describe each one (for a product: name, price, availability, ratings). These descriptions are embedded in the page code in one of three formats: Google's recommended JSON-LD (a data block separate from the visible content), Microdata (attributes on HTML tags) or RDFa. JSON-LD is the most convenient because it does not mix with the presentation layer and is easy to generate dynamically.

When a crawler encounters valid markup, it builds a structured understanding of the page and may qualify it for rich results — with star ratings, prices, recipe preparation times or an expandable list of questions.

Practical application

An online store marks products with the Product type including price and availability, so ratings and price ranges appear in the results. A publisher describes posts as Article with author and date, while a local business uses LocalBusiness with address and opening hours to support local SEO. Correct implementation is checked with Google's Rich Results Test and in Search Console. The cardinal rule: markup must reflect content visible to the user — tagging data that is not on the page is treated as spam.