What is JSON-LD?

The W3C describes JSON-LD 1.1 as "a JSON-based format to serialize Linked Data". It became a W3C Recommendation on 16 July 2020 (W3C, read 1 November 2026). The project site puts it more simply: "JSON-LD is a lightweight Linked Data format. It is easy for humans to read and write" (JSON-LD.org).

The name is spelled out in different ways. The project site's title says "JSON for Linked Data"; the W3C title says "A JSON-based Serialization for Linked Data". Both mean the same thing: JSON with a few extra keys that give the data shared meaning.

Why does JSON-LD matter for SEO?

It is the usual way to add structured data. Google says "Google recommends using JSON-LD for structured data if your site's setup allows it", while "all 3 formats are equally fine for Google" (Google Search Central). The other two formats are Microdata and RDFa.

For a B2B SaaS team the practical gain is upkeep. JSON-LD sits in one block, apart from the visible HTML. A developer can add it to a page template once, and every new blog post or product page gets it.

How does JSON-LD work?

You put a script tag with type `application/ld+json` on the page and write a JSON object inside it. Three keys do most of the work. The W3C definitions:

  • `@context`: "Used to define the short-hand names that are used throughout a JSON-LD document." For SEO this is almost always `https://schema.org`.
  • `@type`: "Used to set the type of a node or the datatype of a typed value." For example `Organization` or `Article`.
  • `@id`: "Used to uniquely identify node objects". It lets one block point to another, such as an article pointing to its publisher.

What does JSON-LD look like? (hypothetical example)

A hypothetical example for a company called Example Analytics:

`{"@context": "https://schema.org", "@type": "Organization", "name": "Example Analytics", "url": "https://example.com", "logo": "https://example.com/logo.png", "sameAs": ["https://www.linkedin.com/company/example"]}`

The `sameAs` list links the company to its profiles elsewhere. See sameAs.

What are common JSON-LD mistakes?

  • Marking up facts that are not on the page. Google: "Don't mark up content that is not visible to readers of the page."
  • Letting the markup go stale, such as an old price or an old date.
  • Broken JSON, such as a missing comma, which can stop the whole block from being read.
  • Expecting a rich result. Google "does not guarantee" that structured data will show up.

Quotes in this list are from Google's general structured data guidelines.

JSON-LD vs schema markup

JSON-LD is the format. Schema markup is the vocabulary you write in it. On AI search, Google says "Structured data isn't required for generative AI search" (Google Search Central). For what does move AI answers, see our guide to LLM SEO.