JSON-LD
JSON-LD (JavaScript Object Notation for Linked Data) is the format Google recommends for embedding schema.org structured data as a self-contained script block in the HTML of a web page, so that search engines and AI systems can read its content in machine-readable form.
In practice
JSON-LD keeps the markup cleanly separated from the visible HTML, which makes it easier to maintain than the older Microdata format. Typical uses are Organization, LocalBusiness, BreadcrumbList, Article and DefinedTerm — the technical basis for rich results and for being classified correctly by AI search systems.