Can Schema Markup Validator combine JSON-LD with HTML annotations?

Definition: Yes. Schema.org's Markup Validator extracts JSON-LD from script elements together with RDFa and Microdata annotations in HTML, then displays a summary of the extracted structured data graph. It validates Schema.org-based structured data and, for JSON-LD, does not fetch or interpret other @context URLs.

Key facts

• Schema.org's validator documentation lists JSON-LD 1.0, RDFa 1.1, and Microdata as supported markup formats.
• The service can fetch a page from a URL or validate markup supplied directly, according to the same documentation.
• The validator can extract structured data injected by JavaScript, such as data added by widgets.
• Its documented combined input is JSON-LD from script elements alongside data expressed by RDFa and Microdata HTML attributes.
• The validator identifies syntax mistakes and displays a summary of the extracted structured data graph.

How does the validator combine the formats?

The validator accepts either a page URL or markup entered directly. For a page, its documented extraction covers JSON-LD in script elements and data expressed through RDFa and Microdata attributes. It then reports the extracted result as a structured data graph summary. The page also says that it can process structured data injected by JavaScript, which matters when the initial HTML differs from the rendered page.

An illustrative mixed input can place the three syntaxes in one HTML document:

<script type="application/ld+json">
{"@context":"https://schema.org","@type":"Person","name":"Example"}
</script>

<div vocab="https://schema.org/" typeof="Person">
  <span property="name">Example</span>
</div>

<div itemscope itemtype="https://schema.org/Person">
  <span itemprop="name">Example</span>
</div>

The documentation describes combination, extraction, and graph display. It does not specify a precedence rule for conflicting values or a deduplication rule for equivalent entities.

What does each syntax contribute?

JSON-LD is a JSON serialization of Linked Data. The W3C JSON-LD 1.1 specification defines a JSON-LD document as a serialization of an RDF dataset. Schema.org's validator feature list names JSON-LD 1.0, so that is the support level documented on the validator page.

RDFa, or Resource Description Framework in Attributes, adds markup attributes to HTML so that existing human-readable content carries machine-readable hints, as the W3C RDFa Primer explains. Microdata uses HTML attributes to form items made of name-value pairs. The HTML Microdata specification describes itemscope as creating an item, itemtype as giving its type, and itemprop as naming its properties. An itemid can provide a global identifier when the vocabulary supports that feature.

These syntaxes describe data through different surface forms. The validator's documented combination step lets the extracted representations appear in one graph summary.

What should you check in a validation run?

Start with the page URL when the relevant markup is rendered or injected by JavaScript. Use direct markup validation when you need to isolate a fragment. Inspect both the syntax messages and the graph summary because the validator documents those as separate outputs.

Keep the JSON-LD context within the Schema.org scope documented for this service. The validator says it will not fetch or interpret other @context URLs. That limitation affects how a mixed-format test should be read when a JSON-LD block relies on an external vocabulary.

Related terms

• Microdata
• RDFa
• Schema.org @id
• How does Schema.org validation differ from Google's Rich Results Test?

FAQ

Can JSON-LD, RDFa, and Microdata appear on the same page?

Yes. Schema.org's validator documentation explicitly describes JSON-LD from script elements being combined with RDFa and Microdata data from HTML attributes, then included in the extracted graph summary.

Does the validator interpret every JSON-LD context?

No. The documentation limits the tool to Schema.org and says that it will not fetch or interpret other @context URLs in JSON-LD.

Does a graph summary prove that a search feature will use the markup?

The validator page documents extraction, syntax checks, and graph display. It does not describe search-feature eligibility or a citation outcome.

Sources

1. Schema.org, "Validator", 16 September 2026
2. W3C, "JSON-LD 1.1", 16 July 2020
3. W3C, "RDFa 1.1 Primer", 17 March 2015
4. WHATWG, "HTML Standard, Microdata", 19 October 2026

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