SEO Checks · Structured Data
Structured data (JSON-LD) explained: what we check & why it matters
Quick answer: JSON-LD structured data is machine-readable metadata embedded in your HTML that tells search engines what your page is about — a product, an article, an organization. It enables rich results in Google (star ratings, FAQ dropdowns, breadcrumbs) and helps AI systems understand your content. Our engine runs four structured data checks: presence, validity, homepage schema, and breadcrumbs.
What is JSON-LD structured data?
JSON-LD (JavaScript Object Notation for Linked Data) is the format Google recommends for embedding structured data. It lives in a <script type="application/ld+json"> block in your page's <head> or <body>:
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "Article",
"headline": "How to add structured data",
"author": { "@type": "Person", "name": "Jane Doe" }
}
</script>Search engines parse these blocks to understand entities, relationships, and content types — information that's hard to extract reliably from HTML alone. The vocabulary comes from schema.org, a collaborative standard maintained by Google, Microsoft, Yahoo, and Yandex.
Why structured data matters for SEO
Structured data is not a direct ranking factor — Google has said this explicitly. But it unlocks features that dramatically improve visibility:
- Rich results: Star ratings, FAQ accordions, recipe cards, how-to steps, product prices, event dates. Pages with rich results can see 20–30% higher click-through rates than plain blue links.
- Knowledge panel eligibility: Organization schema on your homepage is a prerequisite for appearing in Google's knowledge panel.
- Breadcrumb display: BreadcrumbList schema replaces the raw URL in search results with a readable path (Home › Blog › Post Title).
- Sitelinks search box: WebSite schema with a SearchAction can trigger a search box directly in the SERP for branded queries.
How our engine checks structured data
We run four distinct checks on every page. Here's exactly what each one tests:
Check 1: JSON-LD present
ID: structured-data-jsonld-present
Severity: Warning
Scope: Per page
Logic: We count the number of <script type="application/ld+json"> blocks in the HTML. If the count is zero, the check fails. When it fails, we also generate a suggested JSON-LD snippet — either a WebSite schema (for homepages) or a BreadcrumbList schema (for inner pages) — that you can copy-paste into your template.
Why we flag it: A page with no structured data misses out on every rich result type. Even a minimal BreadcrumbList block gives Google a cleaner SERP display and signals your site hierarchy.
Check 2: JSON-LD valid
ID: structured-data-jsonld-valid
Severity: Critical
Scope: Per page
Logic: For each JSON-LD block on the page, we attempt to parse the JSON. If any block contains malformed JSON (syntax errors, trailing commas, unquoted keys), the check fails and we report the parse error.
Why we flag it: Invalid JSON-LD is invisible to search engines — it's worse than having no structured data at all, because you think you're covered but you're not. Common causes: a CMS template outputs a trailing comma after the last property, or a plugin injects malformed JSON.
Check 3: Homepage Organization or WebSite schema
ID: structured-data-homepage-organization-or-website
Severity: Warning
Scope: Site-wide (homepage only)
Logic: On the homepage (path /), we scan all JSON-LD blocks for an @type of Organization or WebSite. If neither type is present, the check fails. We generate a suggested Organization snippet if missing.
Why we flag it: Organization schema is the foundation for Google's knowledge panel. WebSite schema enables the sitelinks search box. Without either, your homepage is missing the most impactful structured data it can have.
Check 4: BreadcrumbList schema
ID: structured-data-breadcrumbs
Severity: Warning
Scope: Per page (inner pages only)
Logic: For every non-homepage URL, we check whether a JSON-LD block with @type: BreadcrumbList is present. If missing, we generate a suggested breadcrumb snippet based on the URL path segments. The homepage is excluded (breadcrumbs don't apply there).
Why we flag it: BreadcrumbList schema is the easiest structured data win — it replaces the raw URL in search results with a human-readable path. Google shows breadcrumbs for most page types, and the schema takes minutes to implement.
How to read your structured data result
When you run a URL through our free checker, each structured data check shows:
- Pass (green): Valid JSON-LD is present with the expected types. No action needed.
- Warning (yellow) — missing: No JSON-LD found, or the expected schema type is absent. Add the suggested snippet from the report.
- Critical (red) — invalid: JSON-LD is present but contains parse errors. Fix the JSON syntax — the error message tells you exactly what's wrong.
Our report also provides a ready-to-paste JSON-LD snippet for each failing check, pre-filled with data from your page (site name, URL, breadcrumb path).
How to fix structured data issues (by platform)
We have step-by-step fix guides for adding JSON-LD schema on every major CMS:
Structured data and AI visibility
AI retrieval systems (used by ChatGPT, Perplexity, Claude) parse structured data to understand what a page is about, what entities it describes, and how it relates to other content. Clean JSON-LD makes your content easier for these systems to categorize, summarize, and cite accurately.
Organization schema helps AI systems attribute content to the right entity. Article schema helps them extract authorship and publication dates. Product schema helps them answer comparison queries. The more machine-readable context you provide, the more likely your content surfaces in AI-generated answers.
For a complete guide on AI citation optimization, see our How to get cited by ChatGPT, Perplexity & Claude guide.
Check your structured data
Our free checker validates all four structured data checks on your page — presence, syntax, homepage schema, and breadcrumbs. No signup required.
Check your site free →FAQ
What is JSON-LD structured data?
JSON-LD is a way to embed machine-readable metadata in a page's HTML using <script type="application/ld+json"> blocks. It tells search engines what a page is about — a product, an article, an organization — using a shared vocabulary from schema.org.
Does structured data help rankings?
Structured data is not a direct ranking factor, but it enables rich results (star ratings, FAQ dropdowns, breadcrumbs, product cards) that significantly increase click-through rates. Pages with rich results can see 20–30% higher CTR than plain blue links.
Which structured data types should every site have?
At minimum, your homepage should have Organization or WebSite schema, and inner pages should have BreadcrumbList schema. Beyond that, add type-specific schema: Article for blog posts, Product for e-commerce, FAQPage for FAQ sections.
Does structured data affect AI visibility?
Yes. AI retrieval systems use structured data to understand page context, entity relationships, and content type. Clean schema markup makes your content easier for these systems to parse, categorize, and cite accurately.
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