Quick answer
Structured data adds machine-readable meaning to visible page content. JSON-LD is the most convenient format for many sites, but Microdata and RDFa are valid alternatives. NOTABIS separates JSON syntax, presence, and format checks; a valid block or detected attribute does not guarantee a rich result or a ranking change.
What the issue means
JSON-LD is placed in a script block:
<script type="application/ld+json">
{
"@context":"https://schema.org",
"@type":"Article",
"headline":"How to store winter tyres"
}
</script>
Microdata annotates HTML with itemscope and itemprop; RDFa uses attributes such as typeof and property. All formats should describe the same visible page and authoritative entity.
Why it matters for SEO
Accurate structured data can help search engines understand entities and may make a page eligible for supported search features. It is not a ranking guarantee, and syntax alone is not enough. Markup that is hidden, misleading, incomplete, or unrelated to visible content may be ignored or lose feature eligibility.
How NOTABIS detects it
NOTABIS reports invalid JSON-LD when a JSON-LD payload cannot be parsed and passes valid JSON-LD when no JSON parse errors are measured, including when no JSON-LD exists. It records Microdata when itemscope appears and RDFa when typeof or property appears. These checks do not validate the full vocabulary, required properties, values, or feature policies.
How to check it yourself
Inspect View Source and the rendered DOM, parse every JSON-LD block, and trace each entity to visible content. Use Google’s Rich Results Test for a supported feature and Schema Markup Validator for broader vocabulary checks. Compare structured URLs and names with the canonical page and internal data source.
How to fix it
Choose the format your team can maintain, generate it from current content, and include only truthful properties. Use a serializer for JSON-LD, keep entity relationships complete, and remove stale duplicate formats. Validate syntax and the intended search feature after deployment, then monitor warnings and manual actions where applicable.
{
"@context":"https://schema.org",
"@type":"Product",
"name":"Example trail shoe"
}
Do not invent reviews, prices, ratings, or events to satisfy a test.
When this is intentional or does not need fixing
Many pages need no structured data, and a site can use one syntax without the others. Legacy Microdata or RDFa may be correct if it remains accurate. Do not migrate a working implementation solely because another format is fashionable.
Related issues
Read valid JSON-LD, invalid JSON-LD, Microdata, and RDFa. Google’s structured-data policies describe quality and feature requirements.
Run a NOTABIS audit
NOTABIS shows which structured-data syntax and parse results were present in the measured page, leaving feature eligibility to the relevant validator.