Structured data: the practical SEO guide

What is structured data in SEO?

Google defines it as a standardized format for providing information about a page and classifying its content. On a recipe, it specifies the ingredients, the cooking time and the calories. Google’s introduction to structured data (updated on December 10, 2025) details this principle.

The most widely used vocabulary is Schema.org, a joint project of the main search engines. It describes hundreds of types (Article, Product, Event, LocalBusiness, Person) and their properties.

In computing, the expression has another meaning. There, structured data is stored in a fixed model, like the rows and columns of an SQL database. Unstructured data has none (texts, images, videos). In between, semi-structured data (JSON, XML) carries tags without a rigid schema. This page deals only with the SEO meaning: the markup of web pages.

Which structured data formats should you choose?

Google Search reads three formats. All use the same Schema.org vocabulary; only the way it is written changes.

Format	Principle	When to use it
JSON-LD	Script block separate from the visible HTML	By default: format recommended by Google, easy to generate and maintain
Microdata	Attributes added within the content’s HTML tags	Older templates already marked up this way
RDFa	HTML5 attributes linked to the visible content	Linked data ecosystems, rarer in SEO

JSON-LD has a practical advantage: it does not touch the visible template. A CMS or an SEO plugin can generate it from the page’s fields. You do not have to edit the HTML by hand.

What is structured data used for today?

First use: eligibility for rich results. These displays add an image, a price, a rating or a date to the blue link. Google publishes cases from publishers who measured the effect on their clicks.

These figures are cases chosen by Google, with no published control group. They show potential, not an expected result on your site. The effect is on appearance and click-through rate. Google does not present markup as a way to gain positions.

Second use: understanding. Organization or Person markup linked to your official profiles helps search engines identify who is publishing. It supports the consistency of your E-E-A-T and of your brand entity.

Is structured data useful for AI search engines?

Google’s position is explicit. No particular markup or special file is needed to appear in its AI features. Nor is there any dedicated Schema.org structured data (Google documentation on AI features). To be cited in AI Overviews or AI Mode, a page must be indexed and eligible for a snippet.

Markup remains useful indirectly. It describes without ambiguity the author, the update date and the organization, which answer engines cross-check. It does not replace clear, citable content, the first lever to optimize for AI.

Which Schema.org types should you use for your pages?

Page	Schema.org type	What it describes
Blog article, guide	Article or BlogPosting	Title, author, publication and update dates, image
All pages	BreadcrumbList	Breadcrumb trail and position of the page in the site
Home, About	Organization, Person	Identity, logo, official profiles (sameAs)
Product page	Product, Offer	Price, availability, reviews
Local business	LocalBusiness	Address, opening hours, phone number
Event, job posting, video	Event, JobPosting, VideoObject	Dates, location, position, duration

For a local business, LocalBusiness markup complements the Google Business Profile listing. Both show the same name, address and phone number.

Example of JSON-LD markup for an article

Here is a minimal Article markup, to be placed in the page’s head or body. The values are fictitious: each property must reflect information that is actually displayed.

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Article",
  "headline": "301 redirect: the complete SEO guide",
  "datePublished": "2026-09-24",
  "dateModified": "2026-09-24",
  "author": {
    "@type": "Person",
    "name": "First Last",
    "url": "https://www.example.com/about/"
  },
  "publisher": {
    "@type": "Organization",
    "name": "Example",
    "logo": {
      "@type": "ImageObject",
      "url": "https://www.example.com/logo.png"
    }
  },
  "image": "https://www.example.com/images/301-redirect.webp",
  "mainEntityOfPage": "https://www.example.com/seo/301-redirect/"
}
</script>

• @context and @type declare the vocabulary and the type described.
• headline repeats the visible title of the article.
• datePublished and dateModified follow the ISO 8601 format and must match the dates displayed.
• author points to a real author page; publisher describes the publisher.

How do you test and deploy your markup?

1. Validate the syntax with the Schema Markup Validator, which checks compliance with the Schema.org vocabulary.
2. Check eligibility with Google’s Rich Results Test, limited to the types that produce a display.
3. Test one URL per template (article, product, category) rather than page by page.
4. Monitor the enhancement reports in Search Console after deployment.

Google’s quality guidelines (updated on July 10, 2026) set two limits. Markup must be a faithful representation of the visible content. Misleading markup, such as fake reviews, can lead to a manual action that removes eligibility for rich results. And even valid markup does not guarantee any display.

If the JSON-LD is injected with JavaScript, check that it appears in the rendered HTML. The points to watch are detailed in our article on JavaScript SEO. Structured data is part of the technical SEO presented in our SEO guide.