What Is Structured Data? A Guide to Schema.org and JSON-LD

Structured data is information on a web page written in a fixed format, so search engines and AI systems can read it as facts instead of guessing from the running text. A person instantly understands that "1 Example Street, Copenhagen" is an address – a machine needs to be told. That is exactly what structured data does.

In practice, structured data on a website almost always means the schema.org vocabulary written in JSON-LD. It is the format Google recommends, and it is what most tools and CMSs use.

What is structured data – in short

Structured data is a machine-readable description of what a page is about:

• Who is behind it (a company, a person)
• What the page contains (an article, a product, a service, an event)
• How things relate (who wrote the article, which company provides the service, which website the page belongs to)

The information typically sits invisibly in the page's source code. Visitors see no difference, but Google, Bing and AI assistants get an unambiguous picture of the content.

Schema.org: the shared language

For structured data to make sense, everyone has to use the same concepts. That is why Google, Microsoft (Bing) and Yahoo launched the schema.org vocabulary in 2011, soon joined by Yandex. Schema.org defines hundreds of types – such as Organization, Person, Article, Product, Service, Event and LocalBusiness – and the properties each type can have.

When people talk about schema markup, they mean schema.org types added to a page as structured data. You can look up the available types in our schema.org documentation.

The three formats: JSON-LD, Microdata and RDFa

Structured data can be written in three ways:

• JSON-LD – a separate block in the page code, kept apart from the visible content. Easy to maintain and the format Google recommends.
• Microdata – attributes woven directly into the HTML elements.
• RDFa – also attributes in the HTML, mostly used outside SEO.

We compare them in detail in JSON-LD vs. Microdata vs. RDFa. In short: choose JSON-LD unless you have a very specific reason not to.

A concrete example

This is how a company can describe itself with structured data in JSON-LD:

{
  "@context": "https://schema.org",
  "@type": "Organization",
  "@id": "https://www.example.com/#organization",
  "name": "Example Ltd",
  "url": "https://www.example.com",
  "logo": "https://www.example.com/logo.png",
  "address": {
    "@type": "PostalAddress",
    "streetAddress": "1 Example Street",
    "postalCode": "2730",
    "addressLocality": "Herlev",
    "addressCountry": "DK"
  },
  "sameAs": [
    "https://www.linkedin.com/company/example",
    "https://www.facebook.com/example"
  ]
}

Note the @id. It gives the company a stable identity that the rest of the site's structured data can refer to – for example as publisher of articles or provider of services. That is the foundation of what we call entity governance: every page tells the same, consistent story about who you are.

What is structured data used for?

1. Rich results in Google

Structured data can make your pages eligible for enhanced search results – product prices and availability, review stars, breadcrumbs, events or job postings. Google never guarantees they will show, but without structured data the option does not exist at all. See which types trigger rich results in our guide to rich results.

Be aware that Google keeps changing which features exist. FAQ rich results – the expandable questions directly below a search result – have been deprecated (Google added a deprecation notice to its documentation in May 2026), and HowTo is no longer on Google's list of types with rich results. That does not mean FAQ content and FAQ markup have lost their value: questions with clear answers are still strong content for both search engines and AI assistants, and correct structured data helps them understand the page. What has gone is the special display in Google's results.

2. Understanding entities and the Knowledge Graph

Google organises knowledge about companies, people and concepts in its Knowledge Graph. Structured data – especially Organization, Person and sameAs links to your official profiles – helps Google connect your website to the right entity. Read more in Knowledge Graphs: what they are and in our guide to the Google Knowledge Panel.

3. AI search and assistants

AI Overviews, ChatGPT, Perplexity and other assistants also have to work out what a page is about and who is behind it. Clear, consistent data makes your content easier to interpret and cite correctly. We cover this in structured data for AI agents.

Common mistakes

• Marking up content that is not visible on the page. Google's guidelines require structured data to reflect what users can see.
• Conflicting information. When the theme, the SEO plugin and other plugins each add their own Organization with different names or addresses, the picture becomes unclear.
• Missing required properties. A Product without offers, review or aggregateRating does not qualify for product results.
• Outdated types. Markup added only for a feature Google has since removed.
• No connections. Isolated blocks without @id that do not refer to each other.

How to test your structured data

Use two tools, because they test different things:

• Google Rich Results Test shows whether the page qualifies for Google's rich results. We walk through it step by step in Google Rich Results Test: how to use it.
• Schema Markup Validator (validator.schema.org) validates all schema.org markup – including types Google does not use for rich results.

The wider process is covered in testing and validating schema markup.

Should you write structured data yourself?

On a small site you can hand-code a few JSON-LD blocks. The challenge comes as the site grows: every new page needs correct markup, all pages must point to the same entities, and the markup has to keep up when the content or Google's requirements change. That is where an automated workflow pays off – exactly the job AI Schema Generator is built for on WordPress.

Frequently asked questions

Are structured data and schema markup the same thing?

Almost. Structured data is the general term for machine-readable data on a page. Schema markup is structured data that uses the schema.org vocabulary – which in practice is what people mean when they talk about structured data on websites.

Is structured data a ranking factor?

Google has not said that structured data by itself improves rankings. It helps Google understand the content, can make the page eligible for rich results and makes the content easier for AI search to interpret.

Which format should I use?

JSON-LD. It is the format Google recommends, and it is the easiest to maintain because it is kept separate from the page's visible HTML.

Can structured data harm my website?

Not when it is correct and reflects content that is visible on the page. Marking up content that is not on the page, or misleading information, violates Google's guidelines and can lead to a manual action that removes rich results.

How often should structured data be updated?

Whenever the content changes – such as prices, opening hours or authors – and when Google changes its requirements. Markup that no longer matches the page should be fixed or removed.

Summary

Structured data is machine-readable facts about your page, written with the schema.org vocabulary – ideally in JSON-LD. It can earn rich results, helps Google understand who you are, and makes your content easier for AI search to use. What matters is not the amount of markup, but that it is correct, visible on the page and consistent across the whole site.