What is structured data

Structured data for AI

For AI systems, structured data is a set of labeled facts they can pull from a page without having to interpret the prose. A language model reads your paragraphs well, but it can still confuse the author with a person quoted in the text, or mix up two prices. Markup identifies the author and the price directly. Before you rely on it, check that every fact in the markup matches the visible page.

What structured data means

Structured data means data stored in predefined fields with agreed names. A spreadsheet is structured data, and so is a database table. On the web, the agreed names come from Schema.org, a shared vocabulary that the major search engines created and still maintain. It defines types like Person or Organization and lists the properties each type can carry.

How structured data works

Structured data works through a block of code added to a page's HTML that describes the page in Schema.org terms. Google recommends JavaScript Object Notation for Linked Data (JSON-LD), which sits in a script tag and stays separate from the visible content. When a search engine crawls the page, it reads that block and ties the facts to the right entity. In technical SEO, this makes the page eligible for rich results such as star ratings or recipe cards. The markup won't raise rankings by itself, so test it in Google's Rich Results Test, or an SEO audit, before you publish.

A short real-world example

Picture a bakery's contact page that shows its name and street address as ordinary text. Its opening hours appear as ordinary text too. The owner adds a JSON-LD block with the bakery's name and opening hours.

{
  "@context": "https://schema.org",
  "@type": "Bakery",
  "name": "North Street Bakery",
  "openingHours": "Mo-Sa 07:00-15:00"
}

Now a search engine knows the page belongs to a bakery and when it's open, and it doesn't have to work that out from the layout.

Structured data versus unstructured data

Unstructured data has no predefined fields at all. Emails and videos fall into this group, and so does most of the writing on the web. A machine has to infer meaning from unstructured content, and inference can go wrong. Structured data removes that step for the facts you choose to label. Most pages mix both, with free prose for people and markup for machines.

How AI assistants use it

AI assistants use structured data to confirm facts and to connect a page to a known entity. Assistants that answer from a live search index, like Google's AI Overviews, draw on whatever that index has already learned from markup. Clear labels make it less likely that an assistant states the wrong opening hours or credits the wrong company. Keep your organization's name identical across pages, and use the sameAs property to point to your official profiles.

Why schema markup matters

Schema markup matters for SEO because it decides whether a page can appear with enhanced features in search results. A listing that shows a rating or a price takes up more space than a plain blue link and gives searchers more reasons to click. The markup also helps Google tell entities apart, which matters when two brands share a name. The common mistake is to mark up content the visitor can't see. Google treats that as spam and can drop the rich results.

Related terms worth knowing

Schema markup

Schema markup is the code that uses the Schema.org vocabulary. Structured data is the broader idea, and schema markup is the way websites put it into practice.

JSON-LD

JSON-LD is one format for writing schema markup. Microdata and RDFa are older options that add attributes directly to HTML tags. JSON-LD is easier to maintain because it sits in a single block.

Knowledge graph

A knowledge graph is a search engine's database of entities and how they relate to each other. Structured data feeds it, but the graph also draws on sources beyond your site.

Rich results

Rich results are the enhanced search listings that markup can unlock. Eligibility doesn't guarantee that Google will show them. Now that you know what is structured data, run one of your own pages through the Rich Results Test to see which types it already carries.