Structured data (JSON-LD)
A hidden block of JSON that spells out a page's facts (product, price, rating, author) in a format search engines can parse.
See it
What it is
Structured data is a machine-readable description of what a page is about, written against the shared vocabulary at schema.org: this is a Product, its price is 49 USD, it has 128 reviews averaging 4.6. JSON-LD is the format Google prefers, a single <script type='application/ld+json'> block in the head or body that sits alongside your HTML rather than tangling with it (the older alternatives, Microdata and RDFa, decorate the markup itself).
Add it when a page has facts worth parsing: Article, Product with Offer and AggregateRating, Recipe, Event, JobPosting, FAQPage, BreadcrumbList, Organization, LocalBusiness, SoftwareApplication. It is also increasingly how AI assistants pull clean facts about you instead of guessing from prose. Validate with the Rich Results Test and Schema.org's validator; Search Console reports errors per type once you ship.
Two traps. Structured data is not a ranking factor: it makes you eligible for rich results, it does not push you up the page, and eligibility is never a guarantee. And every claim must match what a human sees on the page. Marking up review stars that appear nowhere onscreen, or prices you do not actually list, is a spam violation that gets your markup (sometimes your site) demoted.
Ask AI for it
Add JSON-LD structured data to this site using schema.org types. Emit a <script type='application/ld+json'> block per page: Organization plus WebSite with SearchAction on the homepage, Article (headline, datePublished, dateModified, author, image) on posts, Product with Offer and AggregateRating on product pages, and BreadcrumbList everywhere there is a trail. Generate the values from real page data so nothing is claimed that a visitor cannot see, use absolute URLs and @id references to link the entities, and validate the output against Google's Rich Results Test.