schema.org
An open vocabulary for describing entities (businesses, products, events, people) on the web in a machine-readable way. Co-founded by Google, Microsoft, Yahoo, and Yandex in 2011.
Schema.org is a community-led vocabulary that describes entities on the web. If your business is a law firm, schema.org has a LegalService type with specific fields for practice areas, bar admissions, and consultation availability. If you sell products, Product has fields for price, brand, availability, and ratings.
The vocabulary launched in 2011 as a joint effort between Google, Microsoft, Yahoo, and Yandex. It has been refined annually since. The current version covers more than 800 types and 1,400 properties.
Three formats can carry schema.org data on a page: Microdata (inline HTML attributes), RDFa (similar to Microdata but more flexible), and JSON-LD (a single script block in the head). Google and the major AI engines recommend JSON-LD.
Related terms
JSON-LD
A lightweight JSON format for marking up structured data on web pages. The format Google recommends and the one AI assistants parse most reliably.
structured data
Information on a web page marked up using a shared vocabulary, usually schema.org, so machines (search engines, AI assistants, social cards) can understand what the page is about.