Structured data

Structured data is standardized, machine-readable markup added to a web page's code to describe what the content actually is — telling search engines that a block of text represents a product with a price, a recipe, an event, an article, a review score, or a company's contact details. The dominant vocabulary is schema.org, and Google's recommended serialization is JSON-LD: a script block embedded in the page that describes the content without touching the visible HTML.

How structured data works

A crawler can read the words on a page, but it has to infer their meaning. Structured data removes the guesswork: instead of deducing that “$49.99” is a price, the algorithm receives an explicit Product entity with name, price, and availability properties. Alternative formats — Microdata and RDFa — weave attributes directly into HTML tags, but JSON-LD has become the de facto standard because it keeps the semantic layer separate from the template, which makes it far easier to generate and maintain. Valid markup makes a page eligible for rich results such as star ratings, prices, FAQs, breadcrumbs, and carousels — though eligibility never guarantees display, as Google decides case by case.

Practical applications

The most common structured data deployments include:

• e-commerce — Product markup with price, availability, and ratings, surfaced directly in search results and Google Shopping;
• publishers — Article, FAQPage, HowTo, and BreadcrumbList types that enrich SERP snippets;
• local businesses — LocalBusiness with address, opening hours, and geo data;
• job boards and event sites — JobPosting and Event markup feeding dedicated search modules.

Mainstream CMS platforms generate basic markup automatically or via plugins, while custom sites implement it in templates and validate with Google's Rich Results Test. Although structured data is not a direct ranking factor, an enhanced snippet occupies more SERP real estate and earns a higher CTR — which is why it is now considered a standard part of technical SEO rather than an optional extra.