Schema.org is a collaborative vocabulary of structured data types and properties that search engines (and AI engines) use to understand the meaning of web content.
Originally launched in 2011 by Google, Microsoft (Bing), Yahoo, and Yandex, schema.org defines hundreds of types — Product, Organization, Person, Article, Recipe, Event, Review, BreadcrumbList, FAQPage, HowTo, and many more. Each type has properties: a Product has name, description, image, offers, brand, aggregateRating, and 2026-required fields like hasMerchantReturnPolicy and shippingDetails.
Schema.org is typically emitted as JSON-LD (JavaScript Object Notation for Linked Data) embedded in <script type="application/ld+json"> tags. The legacy alternatives — Microdata and RDFa — are still supported but rarely used in 2026.
Beyond Google rich-result eligibility, schema.org powers AI engines' ability to summarize product, business, and content data for citation in answer interfaces.