What is Schema?
Schema (or Schema.org) is a markup vocabulary that describes the content of a web page in a language machines understand. It is also called structured data. In practice, it is code invisible to the visitor, added to your site, that tells search engines and AI who you are, what you offer and what each page is about.
- Schema describes your site to machines (Google, AI), not to visitors.
- It is invisible on the page: it does not change the design.
- It triggers rich results (stars, FAQ, breadcrumbs).
- It is essential to be understood and cited (SEO and GEO).
Definition: Schema in one sentence
Schema.org is a shared vocabulary, created by Google, Microsoft, Yahoo and Yandex, that lets you "label" the information on a page: a company name, an address, a price, a review, a question-answer, an article, an author. Without this markup, a machine sees text; with it, it understands the meaning of that text.
A simple image: on a shelf, Schema is the labels that tell a machine "this is a product", "this is its price", "this is a customer review". The visitor only sees the shelf.
What is Schema for?
Schema solves a simple problem: engines and AI have to guess the meaning of a page from its text. Schema gives them the answer directly, without ambiguity. It serves three purposes:
- To be better understood by Google and artificial intelligence.
- To earn rich results in search pages.
- To make your site easier to cite by AI (the heart of GEO).
Rich results
When Schema is done well, Google can display your page in a richer form than a plain blue link. A few examples you have already seen:
- The review stars under a product or a service.
- The questions and answers (FAQ) expandable directly in the results.
- The breadcrumb showing the site's structure.
- The business information (hours, address, phone) in the right-hand panel.
These enriched displays catch the eye and increase the click-through rate, at equal ranking.
Schema and GEO: why it matters for AI
AI engines like ChatGPT, Perplexity or Google AI Mode must choose, quickly and reliably, the sources they cite. A well-marked-up page clearly tells them what it is about, who wrote it and which company it belongs to. The result: it is easier to understand and to cite.
That is why Schema is a pillar of GEO, AI search optimization. A site without structured data leaves the machine guessing; a well-marked-up site gives it the answer.
The most useful Schema types
Depending on your activity, some Schema types matter more than others:
- Organization / LocalBusiness: your company, its contact details, its profiles.
- Person: the author or director (a strong trust signal).
- FAQPage: your questions and answers, often reused by AI.
- Product / Offer: your products, prices and availability (e-commerce).
- Article / BlogPosting: your articles and guides.
- BreadcrumbList: the breadcrumb.
- Review / AggregateRating: reviews, when legitimate.
Done well or badly: the consequences
Done well, Schema triggers rich results, strengthens the understanding of your site and makes it easier for AI to cite. Done badly or missing, engines misread your pages, you miss the enriched displays, and AI ignores you more easily. Erroneous Schema (describing elements absent from the page) can even be penalised by Google. The golden rule: Schema must always match the visible content.
Frequently asked questions
Is Schema visible to visitors?
No. It is invisible code added to the page that does not change its appearance. It is meant only for machines: search engines and artificial intelligence.
Which Schema format should I use?
The format recommended by Google is JSON-LD: a block of code placed in the page, separate from the visible content. It is the easiest to maintain and the most reliable.
Do I need a developer for Schema?
Not always: some plugins generate basic Schema. But precise, complete and error-free Schema, tailored to your activity, is often built custom to avoid the approximations that make it useless.
Is your site well marked up?
Good Schema is one of the foundations for being understood by Google and cited by AI. Score GEO analyses your site, checks your structured data and gives you a clear, free diagnostic.