What is Structured Data?
Structured data is machine-readable markup, usually JSON-LD following the schema.org vocabulary, that states explicitly what a page is about — its type, author, price, questions and answers — instead of leaving those facts to be inferred from prose.
Also known as: schema markup, JSON-LD, schema.org
The value is disambiguation. Prose is ambiguous to a parser: a number on a pricing page might be a price, a plan limit or a phone number. Markup removes the guess by labelling it.
For generative engines the benefit is less about rich results and more about entity resolution. Nodes wired together with stable @id values — an Organization referenced by the same identifier from the site, the product listing and the breadcrumbs — describe one entity. The same facts as three unlinked blocks describe three, and a model that cannot resolve a name to a single thing is measurably less likely to cite it.
Markup must match what the page visibly says. Structured data contradicting the rendered content is a policy violation and can remove a site from rich results entirely.
Why Structured Data matters
It is the one place a page can state facts about itself unambiguously, in a form both search engines and language models parse without inference.
JSON-LD is the preferred format
Google recommends JSON-LD over microdata or RDFa for new implementations.
Wire nodes with @id
Referencing one Organization by @id from every block forms a single graph rather than repeated anonymous objects.
Never mark up invisible content
Markup describing content absent from the page violates guidelines and risks losing rich result eligibility.
Do not invent ratings
Fabricated aggregateRating is both a schema violation and a common cause of manual action.