HTML specification for embedding structured data within page content, an alternative to JSON-LD for schema markup implementation.
Microdata is an HTML5 specification that allows webmasters to embed structured data directly within HTML content using specific attributes like itemscope, itemtype, and itemprop. Unlike JSON-LD, which sits in script tags separate from visible content, microdata annotations wrap around the actual text and elements users see on the page.
This approach to structured data markup creates a direct connection between what search engines understand and what users experience. While JSON-LD has become Google's preferred format for most schema implementations, microdata remains valuable for certain use cases where tight integration between markup and content is essential.
Why It Matters for AI SEO
AI-powered search systems and large language models increasingly rely on structured data to understand content context and relationships. Microdata provides this structure in a way that closely mirrors how humans consume information on a page, making it particularly valuable for AI systems that analyze both content and markup simultaneously. Google's crawlers and AI systems can more easily validate microdata accuracy since the structured data directly corresponds to visible page elements. This reduces the risk of markup-content mismatches that can occur with JSON-LD implementations, where developers might accidentally provide schema data that doesn't match the actual page content. For AI content generation tools and SEO platforms, microdata offers a clearer mapping between semantic meaning and displayed information.
How It Works
Microdata implementation involves three main attributes. The The biggest microdata mistake is over-marking content, where every possible element gets wrapped in schema properties even when it doesn't enhance understanding. This creates cluttered HTML that's harder to maintain without providing SEO benefits. Another frequent error is mixing microdata with JSON-LD on the same page for identical schema types, which can confuse search engines and create conflicting signals about the same content.itemscope attribute defines the boundary of an item, itemtype specifies the schema.org vocabulary being used, and itemprop identifies individual properties within that schema. For example, a local business listing might use Business Name
555-1234.
Tools like Google's Rich Results Test can validate microdata implementations, while crawling tools like Screaming Frog and Sitebulb can audit microdata across entire sites. The key advantage is that content creators can add semantic meaning without duplicating information—the same text that users read also provides structured data to search engines.Common Mistakes