What is schema.org?
schema.org is the shared vocabulary of types and properties, jointly maintained by Google, Microsoft, Yahoo and Yandex, that structured data markup uses to describe things on a page.
schema.org itself does not do anything to a page. It is a dictionary: it defines that a Product has a price and an availability, that an Organization has a sameAs, so that different sites describing the same kind of thing use the same words for it. Markup only works because the publisher and the engine reading it agree on this vocabulary in advance.
The vocabulary has to be attached to a page in some concrete syntax, and that is a separate choice. JSON-LD is the syntax Google recommends and the one worth defaulting to; microdata is the older alternative, embedded directly in the visible HTML. Two pages using schema.org's Product type, one in JSON-LD and one in microdata, are saying the same thing in different handwriting, and an engine reading either treats them identically.
Related
- Structured dataStructured data is machine-readable markup, usually schema.org JSON-LD, that states explicitly what a page and its subject are.
- JSON-LDJSON-LD is the syntax for writing schema.org structured data as a self-contained script block, separate from the HTML a visitor actually sees.
- MicrodataMicrodata is the older way of writing schema.org markup, using itemscope and itemprop attributes added directly to the HTML tags a visitor sees, rather than a separate data block.
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