What Is Structured Data? How Schema Markup Helps Search Engines
Structured data is a standardized format for providing information about a page's content and categorizing it, most commonly implemented using vocabulary from Schema.org — a joint effort maintained by Google, Microsoft, Yahoo, and Yandex. Google's documentation explains that structured data helps search engines understand the content and context of a page beyond what plain text alone conveys, and can make a page eligible for enhanced search result features, or "rich results."
Definition
Structured data uses a shared vocabulary — predominantly Schema.org — to label specific pieces of content on a page (a product's price, a recipe's cook time, an article's author) in a format machines can reliably parse, rather than relying on inference from unstructured text and layout. Established
What Schema.org Is
Schema.org is a collaborative vocabulary maintained by Google, Microsoft, Yahoo, and Yandex, defining thousands of types (like Article, Product, Recipe, Organization) and the properties each type can have. It is a vocabulary specification, not a search engine feature itself — individual search engines then decide which schema types they support for rich results. Established
Implementation Formats
| Format | How it's implemented |
|---|---|
| JSON-LD | A separate script block, decoupled from visible HTML — Google's preferred format. |
| Microdata | HTML attributes (itemscope, itemtype, itemprop) added directly to existing elements. |
| RDFa | HTML attributes based on the RDFa specification, also embedded directly in markup. |
Rich Results It Can Unlock
Valid, policy-compliant structured data can make a page eligible for enhanced result formats in Google Search — such as recipe cards with ratings and cook time, product listings with price and availability, or breadcrumb trails shown in place of a raw URL. Google's documentation is explicit that adding structured data does not guarantee a rich result will actually appear; eligibility is necessary but not sufficient. Established
Google's Structured Data Guidelines
Google requires structured data to accurately reflect the page's main, visible content — not describe something absent from the page, and not be used to manipulate rankings or deceive users. Violating these guidelines can result in structured data being ignored for rich results, or in more severe cases, a manual action against the site. Established
Common Mistakes
- Marking up content that isn't visible on the page. Google's guidelines require structured data to reflect real, visible page content.
- Using deprecated or unsupported schema types for rich results. Not every Schema.org type is eligible for a Google rich result feature, even if it's valid vocabulary.
- Mixing formats inconsistently for the same data. Using both Microdata and JSON-LD for the same entity on one page can create confusing or conflicting signals.
- Expecting a rich result guarantee. Valid structured data makes a page eligible, but Google independently decides whether to actually display the enhanced format.
FAQ
Does structured data guarantee a rich result?
No. Google's documentation states structured data makes a page eligible for rich results, but Google decides independently whether to display them based on additional quality and relevance factors.
Is Schema.org owned by Google?
No. Schema.org is a joint, collaborative effort maintained by Google, Microsoft, Yahoo, and Yandex, not owned or controlled solely by any one company.
What's the difference between JSON-LD, Microdata, and RDFa?
They're three different syntaxes for expressing the same structured data. JSON-LD uses a separate script block; Microdata and RDFa embed attributes directly into existing HTML elements. Google recommends JSON-LD where supported.
Related Concepts
Sources
- Google Search Central. "Intro to How Structured Data Markup Works." developers.google.com
- Schema.org. "About Schema.org." schema.org