Structured Data & Rich Snippets

html_lesson_09_2 already taught the markup mechanics of microdata and Schema.org. What it didn't cover is why a search engine cares — this chapter delivers that half in full: structured data as a direct line to a richer, more clickable search result.

What Structured Data Actually Does

A page's own visible text tells a human reader what it's about. Structured data tells a machine the exact same thing, unambiguously — this is a recipe, this field is the cook time, this field is the rating. Without it, a search engine has to infer meaning from plain prose; with it, the meaning is stated directly, in a format built specifically to be machine-read.

JSON-LD — The Practical Default

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Article",
  "headline": "Hiragana Stroke Order Guide",
  "author": { "@type": "Person", "name": "Philip Osztromok" },
  "datePublished": "2026-01-15"
}
</script>

html_lesson_09_2 covered inline microdata (itemscope/itemprop attributes woven directly into visible HTML). JSON-LD does the identical job — describing the same schema.org vocabulary — as one self-contained script block, entirely separate from the visible markup. This is now the format Google's own documentation recommends by default, specifically because it doesn't require touching the page's own display HTML at all.

The Actual Payoff — Rich Snippets

A Real Gotcha: Marked-Up Data Must Match Visible Content

Structured data claiming a 5-star rating on a page that shows no visible rating anywhere is a real, documented policy violation, not a clever trick — search engines actively check for this mismatch and can remove rich-result eligibility (or apply a manual penalty) for structured data that misrepresents what's actually on the page.

Hands-On Exercises