What Is Structured Data?
Structured data is markup that describes your page content in a machine-readable format. It uses vocabulary defined by schema.org — a collaborative initiative founded by Google, Microsoft, Yahoo!, and Yandex — to explicitly communicate the type and attributes of your content.
There are three formats — JSON-LD, Microdata, and RDFa — but Google recommends JSON-LD for its ease of management. JSON-LD is written in a standalone <script> tag without modifying your HTML content.
/* JSON-LD basic structure */
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "Article",
"headline": "ページのタイトル",
"author": {
"@type": "Person",
"name": "著者名"
},
"datePublished": "2026-04-25"
}
</script>Why Does Structured Data Matter?
When properly implemented, structured data can enable rich results in Google Search — visually enhanced listings that go beyond the standard blue link. FAQ dropdowns, star ratings, breadcrumbs, and price information all increase visibility and click-through rates.
+20–30%
Average CTR increase when rich results are shown
~35%
Sites with correctly implemented structured data
3 formats
JSON-LD, Microdata, and RDFa supported by Google
Key Schema.org Types
Schema.org defines hundreds of types, but the following six are most impactful for SEO. Each type enables different rich result features in search.
| Type | Use Case | Rich Result Effect |
|---|---|---|
| FAQPage | FAQ pages | Q&A accordion appears in search results |
| Article | Blog posts & news | Author, date, and thumbnail shown |
| Product | Product pages | Price, rating, and availability shown |
| BreadcrumbList | Breadcrumb navigation | Path shown instead of raw URL |
| Organization | Company/organization info | Info appears in Knowledge Panel |
| LocalBusiness | Local shops & businesses | Shown in Maps & local search |
JSON-LD Code Example: FAQPage
FAQPage is one of the highest-impact schema types. It can display Q&A accordions directly in search results, increasing the visual footprint of your listing and boosting CTR.
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "FAQPage",
"mainEntity": [
{
"@type": "Question",
"name": "構造化データとは何ですか？",
"acceptedAnswer": {
"@type": "Answer",
"text": "構造化データとは、Webページの内容を検索エンジンが理解しやすい形式で記述するマークアップです。"
}
},
{
"@type": "Question",
"name": "JSON-LDはどこに書けばいいですか？",
"acceptedAnswer": {
"@type": "Answer",
"text": "HTMLの<head>内に<script type=\"application/ld+json\">タグで記述します。"
}
}
]
}
</script>Note: The Q&A content in FAQPage must match text that is actually visible on the page. Adding hidden content or Q&As not present on the page violates Google's guidelines.
Common Mistakes to Avoid
Missing @context
Without "@context": "https://schema.org" at the top of your JSON-LD, Google cannot identify the vocabulary namespace and will return an error. Include it in every JSON-LD block.
Structured data doesn't match page content
If information in your structured data (price, rating, FAQ text) is not actually visible on the page, it violates Google's guidelines and risks a Manual Action penalty.
Missing required properties
Each schema.org type has required properties. For example, Product requires "name". Use Google's Rich Results Test before publishing to catch missing properties.
JSON syntax errors
Missing commas, unclosed brackets, or mismatched quotes will invalidate your entire JSON-LD block. Always validate with a JSON linter or the Rich Results Test.