STRUCTURED DATA · SEO GLOSSARY
Schema Validator
A tool for testing and validating schema.org structured data markup — checking JSON-LD, Microdata, or RDFa for syntax errors, missing required properties, and compatibility with Google\'s rich result requirements. Google\'s Rich Results Test and Schema.org Validator are the primary official validators; third-party tools including DeepSEOAnalysis provide per-URL validation with server-rendering detection.
Definition
A schema validator is a tool that parses structured data markup from a URL or code snippet and evaluates it for correctness against schema.org specifications and Google\'s rich result requirements. Primary schema validation tools: **Google\'s Rich Results Test** (search.google.com/test/rich-results) — the official Google tool that shows which rich result types a page is eligible for, highlights missing or invalid properties, and indicates whether the schema is correctly parsed by Google\'s renderer. Tests URLs or code snippets. **Schema.org Validator** (validator.schema.org) — the schema.org organisation\'s own validator, which tests against the full schema.org specification rather than specifically Google\'s rich result subset. **DeepSEOAnalysis** — per-URL validation that adds server-rendering detection (whether schema is in the initial HTML vs JavaScript-injected), property-level gap analysis across all schema types on the page, and cross-check between schema values and visible page content. **Structured Data Testing Tool** (deprecated Google tool, partially replaced by Rich Results Test). What validators check: (1) **Syntax validity**: correctly formed JSON, correct use of `@context` and `@type`, valid property names. (2) **Required property presence**: each rich result type has required properties — validators flag missing required fields. (3) **Property type correctness**: for example, `aggregateRating.ratingValue` should be a number or numeric string — validators flag type mismatches. (4) **Eligibility**: Rich Results Test indicates whether the page is eligible for a specific rich result type (e.g., Review snippets, FAQPage, Product). What validators typically don\'t check: **Server-rendering**: most validators including Google\'s Rich Results Test execute JavaScript and test the rendered DOM — they don\'t distinguish between schema in the initial HTML (reliable) and schema added by JavaScript after render (inconsistently processed by Googlebot). DeepSEOAnalysis explicitly tests for server-rendering by comparing initial HTML response against rendered DOM.
Why it matters for SEO
Structured data errors are silent — a page with incorrectly implemented schema receives no error in Search Console by default, and rich results simply don\'t appear without explanation. Schema validators surface these silent errors: missing required properties that prevent rich result eligibility, syntax errors that cause parsing failures, and property mismatches that trigger quality checks. Running schema validation before and after implementing structured data changes is the standard verification step for confirming rich result eligibility.
How DeepSEOAnalysis checks this
DeepSEOAnalysis validates structured data on every audited URL: parsing all JSON-LD blocks in the initial HTML response, identifying schema types, checking required and recommended properties for each type, and comparing schema values against visible page content (e.g., flagging aggregateRating values in schema that don\'t match the rating displayed on the page). The server-rendering check compares initial HTML against the JavaScript-rendered DOM — a distinction not available in Google\'s Rich Results Test.
Useful tools and resources
GLOSSARY
Related terms
structured data
Structured Data
Machine-readable annotations added to HTML — usually JSON-LD — that explicitly describe what a page is about to search engines and AI systems.
Read definition →structured data
Rich Results
Enhanced search result formats that Google displays beyond the standard blue link, title, and description — including star ratings, FAQ dropdowns, product panels, recipe cards, How To steps, event dates, and job listings — enabled by valid structured data (JSON-LD schema) in the page\'s server-rendered HTML.
Read definition →structured data
Rich Result Eligibility
Whether a web page meets the technical and content requirements for Google to display an enhanced search result (rich result) — including star ratings, FAQ dropdowns, recipe cards, event listings, or product price panels. Eligibility requires correctly implemented server-rendered schema of the appropriate type, required property completeness, and content policy compliance.
Read definition →structured data
JSON-LD
JavaScript Object Notation for Linked Data — Google\'s preferred format for adding structured data (Schema.org markup) to web pages via a `<script type="application/ld+json">` block in the HTML head or body, keeping machine-readable data separate from visible content and easier to maintain than Microdata or RDFa.
Read definition →See how your site scores on Schema Validator.
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