Schema markup is structured data written with the Schema.org vocabulary. It adds machine-readable context to a page so search engines and external services can understand what the page is about more reliably.
Schema markup adds meaning to HTML
The visible page is written for people. Schema markup describes the same page in a more explicit way: whether it is an article, a website, an organization profile, a breadcrumb trail, or a software tool.
Common Schema types
- WebSite: site-level information
- Organization: brand or publisher information
- BreadcrumbList: page hierarchy
- Article: headline, dates, and author details
- SoftwareApplication: app or tool information
JSON-LD is the usual structured data format
Modern sites commonly output Schema markup as JSON-LD inside a script tag. It keeps structured data separate from the visible HTML and is easier to manage from templates or components.
{
"@context": "https://schema.org",
"@type": "Article",
"headline": "What Is Schema Markup?",
"datePublished": "2026-05-06"
}Schema markup checklist
- @context points to https://schema.org
- @type matches the actual page content
- title and description do not conflict with the visible page
- dates, URLs, and generated fields survive template changes
- old or unrelated structured data is not left behind
Schema markup should be reviewed whenever templates, content models, or routing change. Use the TOOLPOOL Schema Checker to detect JSON-LD and microdata from a public URL, then confirm the basic fields before publishing.