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Structured data

Structured data is machine-readable markup (typically schema.org vocabulary in JSON-LD format) that describes the content and meaning of a webpage to search engines and AI systems — required for rich SERP features, helpful but not required for AI Overview citation per Google's 2026-05-15 guide.

Definition

Structured data is markup that describes a webpage's content in a machine-readable format. The dominant vocabulary is schema.org — a shared standard maintained by Google, Microsoft, Yahoo, and Yandex. The dominant serialization format is JSON-LD (JSON for Linked Data), embedded as a <script type="application/ld+json"> tag in the page HTML.

Why it matters

Three distinct SEO + AI search outcomes depend on structured data:

  1. Rich SERP features. Star ratings, prices, recipe cards, event details, FAQ accordions, video carousels, knowledge panels — all require specific schema types correctly implemented.
  2. Entity disambiguation. Schema explicitly states "this brand mention refers to this organization" via sameAs links to authoritative external sources (Wikipedia, LinkedIn, official social profiles). Critical when brand names are common words.
  3. AI search citation context. AI engines parse structured data when composing responses. FAQPage schema in particular gets lifted directly into AIO answer panels and ChatGPT responses.

Google's 2026-05-15 stance

Google's AI Optimization Guide states structured data is not required for generative AI ranking specifically — Gemini composes answers from raw content even without schema. But the guide explicitly notes structured data remains helpful for rich SERP features and for clarifying entity relationships. The cost-benefit math is unchanged: ship structured data for rich results regardless of the AI ranking question.

Highest-leverage schema types

  • Organization — base entity for the site itself. Set on every page.
  • WebSite — enables sitelinks search box, defines site search action.
  • Article — for blog posts and guides. Includes author, datePublished, dateModified.
  • FAQPage — the highest-citation-rate schema for AI search. Inserts question-answer pairs into search engines and AIs.
  • HowTo — step-by-step content. Earns instructional rich results.
  • Product — for product pages with price, rating, availability.
  • BreadcrumbList — navigation hierarchy. Improves SERP appearance.

Common validation pitfalls

  • Invalid JSON. A single unescaped quote or comma breaks the entire block. Use Google's Rich Results Test before deploying.
  • Mismatched on-page content. Schema must accurately describe what's actually on the page. Claiming aggregateRating for a product page with no reviews is a manual-action risk.
  • Multiple conflicting Organization entries. Some sites accidentally render Organization schema in both the layout and individual pages. Consolidate to one canonical entry per page using @id.

See /structured-data-for-ai for the AI-search-specific implementation patterns.

Frequently asked

Is structured data still worth implementing after Google said it's not required for AI search?

Yes. Google's guide says structured data is not required for generative AI ranking specifically. It's still required for rich SERP results, knowledge panels, entity disambiguation, and the structured cards that account for the majority of high-CTR SERP positions. The cost-benefit is unchanged.

Which schema type has the highest citation rate in AI Overview?

FAQPage. AIO frequently lifts question-answer pairs directly from FAQPage schema into its responses, sometimes with the source URL as a citation. ProductSchema and HowTo follow for their respective query intents.

JSON-LD vs Microdata vs RDFa — which format?

JSON-LD. Google recommends it as the preferred serialization, it's the easiest to maintain (lives in a single script tag separate from page content), and tooling around it is the most mature. Microdata and RDFa still work but require inline annotations that mix with content.

Related

Pillar guide
/structured-data-for-ai
Glossary
JSON-LD
Glossary
Generative Engine Optimization (GEO)
Glossary
AI Overview (AIO)

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