STRUCTURED DATA · SEO GLOSSARY
Microdata
Microdata is one of three syntaxes for adding structured data to HTML (alongside JSON-LD and RDFa). It embeds structured data inline in HTML using itemscope, itemtype, and itemprop attributes on existing HTML elements. JSON-LD is now Google\'s recommended format, but Microdata is still valid and indexed.
Definition
Microdata adds structured data annotations directly to HTML elements: **itemscope** — marks an HTML element as the container for a structured data item (e.g., <div itemscope>); **itemtype** — specifies the schema type using a Schema.org URL (e.g., itemtype="https://schema.org/Product"); **itemprop** — marks an element as a property of the enclosing item (e.g., <span itemprop="name">Product Name</span>). Example Microdata Product markup: <div itemscope itemtype="https://schema.org/Product"><span itemprop="name">Blue Wireless Headphones</span><span itemprop="description">Over-ear noise cancelling headphones.</span></div>. **Comparison with JSON-LD**: Microdata is embedded in the visible HTML — every property must correspond to a visible HTML element. This makes it more constrained than JSON-LD, which is a separate <script> block that can include properties not shown to users (like price currency, availability codes, or identifier values that don\'t appear in visible text). JSON-LD also doesn\'t break if the visible HTML is redesigned — Microdata breaks when the HTML structure changes. **Google\'s position**: Google has supported Microdata since it was developed (originally by the WHATWG specification group). Google still indexes and validates Microdata. However, Google\'s documentation and tooling (Rich Results Test, Structured Data Guidelines) now recommend JSON-LD as the preferred syntax. **Migration from Microdata to JSON-LD**: for sites with existing Microdata markup, migration to JSON-LD is not urgently required — Microdata continues to work. However, JSON-LD is easier to maintain and validate, and new structured data should use JSON-LD.
Why it matters for SEO
Microdata is most commonly encountered when auditing older WordPress themes, legacy e-commerce templates, and sites built before JSON-LD became dominant (pre-2016). Sites with Microdata markup may not be using it correctly — either missing required properties, using incorrect itemprop values, or mixing Microdata and JSON-LD in ways that cause duplicate schema errors. Understanding Microdata syntax is necessary to audit and validate these sites correctly.
How DeepSEOAnalysis checks this
The audit detects and validates both JSON-LD and Microdata structured data on crawled pages. For Microdata: the itemscope/itemtype/itemprop attributes are parsed, the inferred schema type and properties are validated against Google\'s Rich Results specifications, and missing required properties are flagged. If both Microdata and JSON-LD are present for the same entity type, a duplicate schema warning is issued.
Useful tools and resources
GLOSSARY
Related terms
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 →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
Product Schema
Product schema is a Schema.org structured data type that describes a product for sale — name, description, image, price, availability, reviews — enabling rich results including price, availability, and star ratings directly in Google Search results. It is the highest-priority structured data type for e-commerce.
Read definition →See how your site scores on Microdata.
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