What is JSON-LD?

JSON-LD, explained

Structured data can be added in three formats. Microdata and RDFa add attributes to your existing HTML elements. JSON-LD keeps everything in one script block, usually in the head, describing the page's entities with @context set to https://schema.org, a @type, and properties. Google's structured data guidelines name JSON-LD as the recommended format, while still supporting the others.

Why it wins in practice: it's separate from your markup, so design changes don't break it; it's easy to generate from the same data that renders the page; and you can describe several entities at once, either as an array or linked together with @id references in an @graph. For a Next.js site, a small <JsonLd> component that serializes an object is all you need.

The rules that matter are Google's content rules, not the format. Structured data must describe content that's visible on the page. Required properties for a feature must be present. Pages carrying it must not be blocked from Googlebot by robots.txt or noindex. And markup that misrepresents the page, like fake reviews, can lead to a manual action that removes rich result eligibility.

Validate before shipping: Google's Rich Results Test checks eligibility for specific features, and the Schema Markup Validator checks general Schema.org validity. After launch, Search Console's enhancement reports list errors per type.

Why it matters for founders

JSON-LD is the easiest structured data to add to a modern site and keep correct as it grows. It's generated from your data, so it stays in sync with the page.

Example

Each blog post renders an Article object with headline, datePublished, dateModified and author, plus a BreadcrumbList, from the post's frontmatter.

Common mistakes

• Hand-writing JSON-LD that drifts from the visible content.
• Unescaped characters that break the JSON.
• Leaving out required properties for the rich result you want.
• Adding markup to pages blocked from Googlebot.