Structured Data
Structured data is the umbrella term for any markup that explicitly declares what a piece of web content means — beyond what plain HTML can express. The most common 2026 formats are JSON-LD (preferred), Microdata, and RDFa, all typically using the Schema.org vocabulary. Structured data is essential for rich results, AI Overview citation, and Knowledge Graph entity recognition.
Also called: Semantic markup, Microdata (deprecated synonym) · Last updated: May 27, 2026 · By Joseph W. Anady
Why it matters.
Structured data answers the question: what does this page describe? HTML alone tells search engines the title, headings, and paragraphs. Structured data adds: this is an Organization named X located at Y selling Z. Without structured data, search engines have to guess via natural-language processing. With it, the meaning is unambiguous.
How it works.
Structured data embeds Schema.org-vocabulary entities and properties into a page. JSON-LD (preferred by Google) does this via a separate script block in the head. Microdata embeds attributes inline on existing HTML elements. RDFa uses a similar inline pattern with different syntax. All three are parsed by Google, but JSON-LD is the cleanest and easiest to maintain.
2026 reality check.
Structured data is now critical for AI Overview eligibility, Featured Snippet capture, and LLM citation. Pages without structured data are increasingly invisible to AI engines that rely on machine-readable signals. The May 2026 removal of FAQ rich snippets didn't reduce the importance of structured data — it shifted the visible reward from SERP accordions to AI engine extraction.
Data points
- Three main formats: JSON-LD (preferred), Microdata, RDFa
- Schema.org is the dominant vocabulary used in structured data (founded 2011)
- Pages without structured data compete at significant disadvantage in AI search (multiple 2026 studies)
- JSON-LD adoption ~60-70% of structured data on indexed pages (2025-2026 industry estimates)
- FAQ rich snippets removed May 7 2026 — but structured data still extracted by AI engines
First-hand insight from ThatDeveloperGuy.
ThatDeveloperGuy treats structured data as foundational infrastructure, not optional add-on. Every page on every client site has Organization + WebSite + relevant content schema (Service, Article, LocalBusiness, etc.). The cost of generating structured data via templating is minimal; the ranking + citation benefit is substantial. Our Lighthouse SEO score 100/100 default depends partly on structured data presence.
How TDG approaches it
TDG's structured data discipline: every page declares Organization + WebSite at minimum. Content pages add the relevant content type (Service, Article, LocalBusiness, Product, Event, FAQPage). Author attribution via Person schema with sameAs chain. Validation runs in CI. No production page ships with broken or missing structured data.
Common mistakes.
- Skipping structured data because 'we don't need it' (Google's AI Overview eligibility requires it)
- Using Microdata instead of JSON-LD (works but harder to maintain)
- Adding only one schema type per page (most pages benefit from 3-6 types)
- Failing to validate after deploy (use Google Rich Results Test)
- Treating structured data as a one-time setup (must update when content changes)
FAQ.
What's the difference between structured data and schema markup?
Structured data is the general category; schema markup typically refers specifically to Schema.org vocabulary structured data. In 2026 conversations they're often used interchangeably.
Is structured data the same as JSON-LD?
No. Structured data is the category; JSON-LD is one format for implementing it. Microdata and RDFa are alternatives, but JSON-LD is preferred by Google.
Do I need structured data for AI search?
Effectively yes. ChatGPT, Claude, Perplexity, and Gemini favor schema-rich pages in their RAG retrieval. Pages without structured data compete at a significant disadvantage.
Will adding structured data fix my ranking problems?
Helps but isn't sufficient. Structured data is necessary infrastructure but doesn't substitute for content quality, internal linking, technical SEO, or backlinks.
Can I add structured data without changing my HTML?
Yes if you use JSON-LD — it lives in a separate script block in the head. Microdata requires modifying inline HTML attributes.
Maintained by Joseph W. Anady at ThatDeveloperGuy. Back to glossary · Suggest a term