What Is Schema Markup? Structured Data Explained
Also known as: Structured data, JSON-LD markup, Schema.org markup
Schema markup is structured data added to a page's code, using the shared Schema.org vocabulary, that explicitly describes the page's content to search engines in a standardised, machine-readable format.
Last reviewed: 3 August 2026 · Reviewed by iNet Ventures Technical SEO Team
In plain English
Search engines can read your page's text, but text is ambiguous — a number could be a price, a rating, or a phone number. Schema markup removes the ambiguity by explicitly labelling that data: "this is a Recipe, its cookTime is 30 minutes, its author is Jane Doe." Google can then use that structured information to build rich results, like star ratings or recipe cards, directly in search listings.
Technical definition
Schema markup uses the shared vocabulary maintained at Schema.org, implemented on-page in one of three formats: JSON-LD, Microdata, or RDFa. Google explicitly recommends JSON-LD because it can be placed as a single, self-contained script block in the page's head or body without being interleaved into the visible HTML, and because Google can read it even when injected dynamically via JavaScript. Google's own Search Central documentation is the definitive reference for which specific Schema.org properties are required, recommended, or optional for a given rich result feature — the full Schema.org vocabulary is broader than what Google Search actually uses.
Quick example
A recipe page might include JSON-LD marking it as a Recipe type with properties for name, image, author, cookTime, and recipeIngredient, enabling Google to display it as a rich recipe card with a photo, star rating, and cook time directly in search results.
Quick facts
| Meaning | Structured, standardised markup that explicitly describes page content to search engines |
|---|---|
| Main category | Technical SEO |
| Used by | Developers and SEOs implementing rich results for recipes, reviews, products, FAQs, jobs, and more |
| Difficulty | Intermediate |
| Importance | High |
| Common examples | Review stars, recipe cards, FAQ dropdowns, product pricing/availability, job postings, breadcrumb trails |
| Still relevant? | Yes. Google actively expands and updates which structured data types are eligible for rich results, and JSON-LD remains its explicitly recommended format. |
Why Schema Markup matters
Schema is not a direct ranking factor, but it is the mechanism that unlocks visually distinct, higher-CTR search results.
It is the gateway to rich results
Star ratings, recipe cards, FAQ dropdowns and similar enhanced listings in Google Search are only possible when a page carries the correct, valid structured data for that feature.
It removes ambiguity for search engines
Structured data lets you state explicitly what a piece of content is — a review, an event, a product — rather than relying on search engines to correctly infer it from unstructured text.
It supports Google's broader understanding of entities
Beyond individual rich results, Google uses structured data across the web to build a broader understanding of entities like people, organisations, and products, which can feed into other Search features.
It is not, itself, a ranking factor
Google is explicit that adding structured data does not directly improve rankings. Its value is in eligibility for enhanced result formats, which can meaningfully improve click-through rate even without a ranking change.
How it works
How structured data moves from your page to a rich result in Google Search.
- 1
1. Markup is added to the page
Structured data describing the page's content is added, typically as a JSON-LD script block, using the appropriate Schema.org type and properties for the content in question.
- 2
2. Google crawls and parses the markup
When Google crawls the page, it reads the structured data (including JSON-LD generated dynamically via JavaScript) and validates it against the specific requirements for that feature.
- 3
3. Eligibility is checked against feature guidelines
Each rich result type has its own required and recommended properties, documented by Google. Missing required properties or violating the general structured data guidelines makes a page ineligible.
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4. The rich result is (potentially) displayed
Even with valid markup, Google does not guarantee a rich result will display — it is one signal among others used to decide the presentation of a listing.
Types and variations
The three formats Google Search supports, and why JSON-LD is preferred.
JSON-LD (recommended)
A self-contained script block, separate from the visible HTML. Easiest to implement, maintain, and generate dynamically via JavaScript or tag managers — Google's explicitly recommended format.
Microdata
An open HTML specification that nests structured data directly within visible HTML using tag attributes, interleaving markup with content.
RDFa
Similar in concept to Microdata, using HTML tag attributes to expose structured properties within visible content, based on a different underlying open standard.
Real examples
A minimal, valid JSON-LD example for a common content type.
Basic Review schema in JSON-LD
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "Review",
"reviewRating": { "@type": "Rating", "ratingValue": "4.5", "bestRating": "5" },
"author": { "@type": "Person", "name": "Jane Doe" }
}
</script>A self-contained JSON-LD block placed in the page head, describing a review with a rating and author, correctly using the schema.org context and Review type.
Markup describing content not visible on the page
Adding review or rating structured data for content that does not actually appear on the visible page violates Google's structured data guidelines and can result in the markup being ignored or a manual action.
Best practices
Follow Google's specific documentation for each feature, not just the general Schema.org spec.
What to do
- Use JSON-LD as the default format unless there is a specific technical reason not to
- Validate markup with Google's Rich Results Test before and after deployment
- Only mark up content that is genuinely visible to users on the page
- Keep structured data in sync with visible content — the markup and the page must actually agree
- Check Google's Search Central documentation for the specific type you're implementing, since it is the definitive source for what Google Search actually requires
What to avoid
- Marking up content that doesn't appear on the page
- Creating blank or empty pages solely to host structured data
- Assuming schema.org's full vocabulary is all supported by Google Search rich results — only a documented subset is
- Ignoring validation errors reported in Search Console's rich result reports
Common mistakes
Assuming schema markup directly boosts rankings
Structured data affects eligibility for rich result formatting, not rankings directly. Google has stated this explicitly in its own documentation.
Marking up invisible or inaccurate content
Structured data must describe content actually visible and accurate on the page. Mismatches between markup and visible content violate Google's guidelines.
Relying on schema.org documentation over Google's own
Schema.org's full vocabulary is broader than what Google Search supports for rich results. Google's own Search Central documentation is the definitive reference for what it will actually use.
Schema as a formatting lever, not a ranking hack
Structured data gets oversold in some corners of SEO as a ranking booster. It isn't one, by Google's own account — its real value is unlocking a more visually prominent, information-rich search listing that can improve click-through rate without changing position. That is still a meaningful, measurable win, but it is a different mechanism than a ranking factor, and treating it as the latter leads to disappointment when markup alone doesn't move rankings.
- Schema markup is explicitly not a direct Google ranking factor
- Its real value is rich result eligibility, which can improve CTR at the same ranking position
- JSON-LD is Google's recommended format for new implementations
- Only a documented subset of the full Schema.org vocabulary is used for Google rich results
How iNet Ventures approaches schema markup
We check structured data as part of technical audits alongside content and link work, since it is a quick, low-risk win once other fundamentals are in place.
Validation before rollout
Any structured data recommendation is checked against Google's Rich Results Test and current Search Central documentation before implementation, to avoid the common mistake of following outdated or generic schema.org guidance.
Continue learning
Frequently asked questions
Does schema markup improve Google rankings directly?
No. Google explicitly states that adding structured data does not directly improve rankings. Its benefit is eligibility for rich result formatting in search listings, which can improve click-through rate at the same ranking position.
Which structured data format does Google recommend?
JSON-LD. Google explicitly recommends it over Microdata and RDFa because it is a self-contained script block that doesn't need to be interleaved with visible HTML, and Google can read it even when generated dynamically via JavaScript.
Can I use any Schema.org type and expect a rich result?
No. Only a documented subset of Schema.org types and properties are actually used by Google Search for rich results. Google's own Search Central documentation, not the general Schema.org spec, defines what is required for each specific feature.
How do I check if my schema markup is valid?
Use Google's Rich Results Test to check a specific URL or code snippet, and monitor the relevant rich result reports in Google Search Console for ongoing validation errors across your site.
Written directly from Google Search Central's structured data documentation and current guidance on supported formats and rich result eligibility.
- Written by:
- iNet Ventures Editorial Team
- Reviewed by:
- iNet Ventures Technical SEO Team
- Published:
- 3 August 2026
- Last reviewed:
- 3 August 2026
Sources and further reading
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