JSON-LD Checker

SEO用のJSON-LD構造化データを検証。schema.org準拠チェック。

Paste or fetch to validate

16 Schema Types

Article, Product, FAQPage, Recipe, Event and more.

URL Extraction

Fetch and validate JSON-LD from any webpage.

Error Report

Detailed errors, warnings, and field info.

Client-side

All processing in your browser. No data uploaded.

JSON-LD Checkerについて

The JSON-LD Structured Data Validator checks your Schema.org markup for errors, missing required properties, and best-practice recommendations. JSON-LD (JavaScript Object Notation for Linked Data) is Google's preferred format for structured data — embedding it in your pages enables rich results like star ratings, recipe cards, FAQ accordions, event listings, job postings, and breadcrumbs directly in search results. These rich snippets dramatically increase visibility and click-through rates. This tool supports 16 Schema.org types including Article, Product, FAQPage, Recipe, Event, LocalBusiness, HowTo, and more. You can paste JSON-LD directly or fetch it automatically from any URL. Validation runs entirely in your browser with no data uploaded to any server.

JSON-LD Checkerの使い方

Paste your JSON-LD code into the editor, or switch to the "Fetch from URL" tab to extract it from a live page.
Click "Load Sample" to see a correctly formatted Article example as a starting point.
Review the validation results panel — a green "Valid" badge means no errors; red "Invalid" means issues need fixing.
Fix any errors listed in red (missing @context, missing required fields) and warnings listed in orange (missing recommended fields).
Once valid, copy the JSON-LD and add it inside a <script type="application/ld+json"> tag in your HTML <head>.
Test your live page in Google's Rich Results Test tool to confirm eligibility for rich snippets in search results.

よくある質問

What is the difference between JSON-LD, Microdata, and RDFa?

All three are formats for embedding structured data in web pages. JSON-LD is a standalone script block in the <head> — it is the easiest to add and maintain and is Google's recommended format. Microdata and RDFa are embedded inline within HTML elements, making them harder to manage and more prone to breaking during HTML changes.

Which schema types are most valuable for SEO?

The types with the highest impact on search appearance are: Article (news ticker, top stories), Product (price, availability, ratings), FAQPage (FAQ accordion in results), Recipe (cooking cards), Event (event rich results), LocalBusiness (knowledge panel), and BreadcrumbList (breadcrumb trail under result URLs).

Does invalid JSON-LD hurt my SEO?

Invalid JSON-LD will not negatively affect your existing rankings, but it will prevent Google from understanding and displaying rich results. Errors like missing required properties or invalid JSON syntax cause Google to silently ignore the markup.

How do I add JSON-LD to a Next.js or React application?

In Next.js, add a <script type="application/ld+json"> tag inside the <Head> component of your page or use the newer metadata API. For React SPAs, inject it via a Helmet component or add it directly to your index.html. The JSON-LD only needs to be present when the page first loads.

Can I have multiple JSON-LD blocks on the same page?

Yes. Google supports multiple <script type="application/ld+json"> blocks on a single page. This is useful for pages that represent multiple schema types — for example, an Article page might also have BreadcrumbList and Organization markup in separate script blocks.

JSON-LD Checkerの完全ガイド：無料オンラインツール

ブラウザ完結で安全・高速なJSON-LD Checker。開発者やクリエイターの作業を効率化

SEO用のJSON-LD構造化データを検証。schema.org準拠チェック。を瞬時に実現する無料ツールです。面倒なソフトのインストールは不要で、安全にブラウザ上で処理できます。

JSON-LD Checkerが選ばれる理由

高速処理: ミリ秒単位で即時実行。
プライバシー保護: データは端末外に送信されません。
完全無料: 登録不要で制限なく利用可能。

簡単な3つの利用手順

JSON-LD Checkerのページを開きます。
データを入力または貼り付けます。
結果を確認してコピーまたは保存します。

機能比較

項目	Metoolzy JSON-LD Checker	他社オンラインツール	専用ソフト
料金	完全無料	制限あり	有料ライセンス
セキュリティ	完全ローカル処理	サーバー送信あり	ローカル処理