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JSON-LD, short for JavaScript Object Notation for Linked Data, is a lightweight format for adding structured data to a web page. It sits in a small script block, describes your content using the schema.org vocabulary, and is read directly by Google and AI systems. It is the recommended way to implement schema markup because it keeps structured data separate from your visible HTML and is easy to maintain.
Introduction
When you add schema markup to a page, you have to write it in some format. JSON-LD is the one Google recommends and the one most AI systems parse cleanly. Understanding it makes the rest of structured data much easier.
It is worth knowing even if you never write it by hand, because it shapes how you plan and maintain a machine-readable site.
The idea behind JSON-LD
JSON-LD is a way to express facts as structured data that both machines and humans can read. It uses simple key and value pairs, like a name paired with your company name, or an address paired with your location, all tied to definitions from schema.org so the meaning is unambiguous.
The linked data part means the facts connect to a shared vocabulary and to other entities, which is exactly what search engines and AI need to place your brand in a wider web of meaning.
Why it is separate from your page content
Unlike older formats that wrapped structured data around your visible HTML, JSON-LD lives in its own script block. Your content and your structured data are kept apart. That separation is the reason it is easier to maintain, easier to generate automatically, and less likely to break when you redesign a page.
Why Google and AI prefer it
Google explicitly recommends JSON-LD for structured data. It is simple to read, simple to validate, and does not depend on the layout of the page. AI systems benefit for the same reasons: a clean, self-contained block of facts is easier to parse than data scattered through the markup.
The result is that a well-formed JSON-LD block gives machines a reliable description of your page, which supports rich results in search and clearer understanding in AI.
How it fits into your site
In practice, each important page carries one or more JSON-LD blocks describing what it is: an Organization block for your brand, an Article block for a piece of content, a FAQPage block for its questions. Because the format is consistent, these blocks can be generated from a template rather than written by hand, which is what makes a large, structured site maintainable.
For which types to use, see our guide to the most important schema types, and for the bigger picture see our complete guide to schema markup.