Schema.org

Schema.org is a shared vocabulary for describing things on the web—people, places, products, events, organizations, and hundreds of other types—launched in 2011 by Google, Microsoft, Yahoo!, and Yandex. Instead of every site inventing its own way to mark up a recipe or a job posting, Schema.org gives everyone a common set of types and properties that search engines and other consumers already understand. It is one of the most widely deployed structured-data vocabularies in existence, even if most people never see it directly.

• Shared types and properties - A large, community-maintained catalog of things and their attributes, so the web speaks a common data language.
• Search-engine backing - Created and used by the major search engines, which rewards adoption with richer results.
• Multiple serializations - Expressed as JSON-LD, Microdata, or RDFa embedded in web pages.
• Extensible vocabulary - Grows through community proposals, including extensions aimed at describing APIs themselves.

In my API work, Schema.org keeps coming up as the vocabulary the web already agreed on—which makes it a natural candidate for describing API resources and improving discovery, even though it never saw the API-landscape adoption I once hoped for. Its WebAPI type extension was an attempt to bring APIs into that shared vocabulary, and the JSON Schema and Postman collections generated from its types show how directly it maps onto schema design work. In the agentic turn, a machine-readable vocabulary that both search engines and AI models already recognize is exactly the kind of shared meaning that makes data and APIs easier to consume.