---
title: "What is Structured data (Schema.org)?"
description: "Structured data (JSON-LD) tells machines what your pages are. Which types matter for AI visibility, and the one rule: never mark up what isn't visible."
canonical: https://see-geo.com/glossary/structured-data
language: en
published: 2026-09-08
updated: 2026-09-08
publisher: SeeGeo
alternates:
  fr: https://see-geo.com/fr/glossary/structured-data
  de: https://see-geo.com/de/glossary/structured-data
---

# What is Structured data (Schema.org)?

Structured data is machine-readable markup — usually JSON-LD using Schema.org vocabulary — that tells crawlers explicitly what a page contains: an organization, a product, an FAQ, an article.

## Which schema types matter most for AI visibility?

Organization (who you are, with a reachable contact), WebSite/WebApplication (what the site is), FAQPage (packages Q&A in exactly the liftable shape answers use), Article with real authorship, and where honest, Product and LocalBusiness. Linked together with stable @id references they form one graph a machine can walk instead of islands it must guess about.

## What's the one rule of structured data?

Never mark up what the visible page doesn't say. Schema describing invisible content — or worse, invented ratings — is the pattern search engines penalize and the exact dishonesty AI systems are learning to discount. The test is symmetry: a human reading the page and a machine reading the markup should come away with the same facts.

[Entity clarity, explained](https://see-geo.com/glossary/entity-clarity)

## How much structured data is enough?

Less than the plugins suggest. The core set — Organization, WebSite, the page's own type, FAQPage where genuine Q&A exists — covers what engines actually consume; stacking every applicable type adds maintenance surface without visibility. Volume is not the axis that matters: one honest, valid, interlinked graph outperforms twelve types of markup that drift from the visible page.

## Frequently asked questions

### What does Structured data (Schema.org) mean?

Structured data is machine-readable markup — usually JSON-LD using Schema.org vocabulary — that tells crawlers explicitly what a page contains: an organization, a product, an FAQ, an article.

### Does structured data directly improve AI visibility?

Indirectly but meaningfully: it removes ambiguity about what you are, which feeds entity confidence, and FAQPage markup hands engines pre-packaged liftable answers. It complements visible content — it never substitutes for it.

### JSON-LD, microdata, or RDFa?

JSON-LD — it's Google's stated preference, lives in one script tag instead of woven through your HTML, and is the format AI toolchains parse most reliably. There's no modern reason to choose the others.

### How do I check my structured data is valid?

Google's Rich Results Test and Schema.org's validator catch syntax; the harder check is honesty — whether the markup matches the visible page. SeeGeo's audit tests both, including whether your schema description has a visible-prose counterpart.

## Related pages

- [What is Entity clarity?](https://see-geo.com/glossary/entity-clarity)
- [What is Content extractability?](https://see-geo.com/glossary/content-extractability)
- [What is E-E-A-T?](https://see-geo.com/glossary/e-e-a-t)