SEO

JSON-LD

Q: What is JSON-LD?

JSON-LD (JSON for Linked Data) is a format for embedding structured data in HTML. It is placed as a <script type="application/ld+json"> in the HTML head or body. Google has recommended it as the preferred Schema.org format since 2015.

Q: What is the advantage over Microdata?

Decoupling from the HTML structure. Microdata requires attributes on visible HTML elements — schema breaks when the layout changes. JSON-LD runs in parallel in the head and remains independent. Maintenance and deployment are considerably easier.

Q: How do you check JSON-LD syntax?

With two tools: (1) the schema.org Validator (validator.schema.org) for schema correctness, (2) the Rich Results Test (search.google.com/test/rich-results) for Google-specific requirements. Rankmio Content Studio validates JSON-LD automatically on publish.

Q: Can you have several JSON-LD blocks?

Yes, or a single @graph array. Google accepts several <script> blocks or a single one using @graph. For structurally related entities (Article + Author + Publisher), @graph is cleaner because references are easier.

Also known as: JSON-LD, JavaScript Object Notation for Linked Data, structured data JSON-LD

JSON-LD (JavaScript Object Notation for Linked Data) is a W3C standard for marking up structured data in a JSON format. In an SEO context it is the implementation variant recommended by Google for Schema.org markup: instead of writing Schema.org properties into HTML tags as Microdata or RDFa attributes, the markup is placed as a clean JSON block inside a <script type="application/ld+json"> tag in the HTML head. The advantage: no interference with the visible HTML tags, easier to generate and maintain, and preferred by Google.

JSON-LD vs. Microdata vs. RDFa

JSON-LD — clean separation, placed in the head as a script tag. Google's recommendation. Today's standard.
Microdata — inline attributes (itemscope, itemtype, itemprop) in HTML tags. An older standard, still supported by Google but not recommended.
RDFa — similar to Microdata with a slightly different syntax (typeof, property, resource). Rarely used.

For new implementations, JSON-LD is the clear recommendation. Existing Microdata implementations do not have to be migrated, but new schema code is written in JSON-LD.

A concrete JSON-LD example

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Article",
  "headline": "What is JSON-LD?",
  "datePublished": "2026-06-17",
  "author": {
    "@type": "Person",
    "name": "Knut Nickol",
    "sameAs": "https://www.linkedin.com/in/knutnickol"
  },
  "about": {
    "@type": "Thing",
    "name": "JSON-LD",
    "sameAs": "https://www.wikidata.org/wiki/Q1639008"
  }
}
</script>

JSON-LD validation

Google Rich Results Test — tests whether the markup meets Google's rich snippet requirements.
Schema.org Validator — checks Schema.org conformity, independently of Google.
JSON-LD Playground — developer-oriented, with a preview of the linked data.
Search Console reports — show markup found live, including error statistics.

Example from practice

Example: A magazine website historically had Microdata markup directly in its HTML tags — something broke with every theme adjustment, and the markup was error-prone. Migration to JSON-LD: one central JSON-LD generator per page type in the theme header, separate from the HTML layout. The result: the markup error rate fell to zero, new schema types became easy to add, and the Google Rich Results Test found 100 % valid markup. Rich snippet visibility improved measurably over the following 8 weeks.

Frequently asked questions

What is JSON-LD?

JSON-LD (JSON for Linked Data) is a format for embedding structured data in HTML. It is placed as a <script type="application/ld+json"> in the HTML head or body. Google has recommended it as the preferred Schema.org format since 2015.

What is the advantage over Microdata?

Decoupling from the HTML structure. Microdata requires attributes on visible HTML elements — schema breaks when the layout changes. JSON-LD runs in parallel in the head and remains independent. Maintenance and deployment are considerably easier.

How do you check JSON-LD syntax?

With two tools: (1) the schema.org Validator (validator.schema.org) for schema correctness, (2) the Rich Results Test (search.google.com/test/rich-results) for Google-specific requirements. Rankmio Content Studio validates JSON-LD automatically on publish.

Can you have several JSON-LD blocks?

Yes, or a single @graph array. Google accepts several <script> blocks or a single one using @graph. For structurally related entities (Article + Author + Publisher), @graph is cleaner because references are easier.

Used in Rankmio for

JSON-LD schema check in the SEO audit

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Last updated: 2026-06-17 · Browse all glossary entries