Schema markup

Schema markup uses the schema.org vocabulary — an open standard maintained by Google, Microsoft, Yahoo, and Yandex — to describe things on the web in a format machines can parse. It defines entities (people, products, businesses, articles), their properties (names, dates, ratings, prices), and the relationships between them.

The recommended format is JSON-LD, embedded in a <script type="application/ld+json"> tag in the page head. JSON-LD is preferred over Microdata and RDFa because it separates structured data from HTML content, making it easier to maintain at scale.

The five highest-impact schema types for most sites:

1. Organization — defines your business as a known entity. The single highest-leverage implementation in 2026 because it powers knowledge panel accuracy and AI citation reliability, even though it produces no visible SERP feature.

2. Article or BlogPosting — for editorial content. Defines headline, author, publish date, and modified date. Required for Top Stories carousels and AI Overview citation.

3. FAQPage — for question-answer content. The single most impactful schema for AEO and GEO. Note that as of January 2026, Google restricted FAQPage rich results to government and health domains in some queries, but the markup still feeds AI Overviews and voice assistants regardless of rich result eligibility.

4. Product — for ecommerce. Combined with Offer and Review schemas, triggers product rich snippets showing price, availability, and ratings. High-converting placement.

5. LocalBusiness — for any business with a physical location. Powers local pack inclusion and Google Business Profile alignment.

The four mistakes that consistently break implementations:

Schema does not match visible content. If your FAQ schema contains questions and answers that are not actually rendered on the page, Google can demote or manually action the markup. The March 2026 core update specifically penalized FAQ, Review, and HowTo schema implemented as SERP manipulation rather than as accurate descriptions of genuine page content.

Stale schema. Product schema with outdated prices, expired events, or out-of-stock items left as available creates user friction and trust penalties. Schema must update whenever the underlying content changes.

Over-marking up everything. Adding schema to elements that do not need it dilutes the impact of your most important structured data and can confuse search engines.

Skipping validation. Errors are silent. They do not break the page; they just prevent rich results from appearing. Quarterly validation catches drift introduced by template changes or content updates.

Three free tools cover validation:

Google Rich Results Test — checks whether a URL or code snippet qualifies for specific rich results and shows previews. Use this for Google-specific markup (FAQ, Product, Recipe, etc.).

Schema.org Validator — validates against the full schema.org specification. Catches errors Google's tool ignores. Use this for thorough syntax checking.

Google Search Console — the Enhancements report shows ongoing schema performance and flags errors at scale. Set up alerts for validation failures so issues surface before they tank rich result eligibility.