What is schema markup?
Schema markup is structured data added to a page in a standard vocabulary, so search engines and AI assistants can read its facts directly rather than inferring them from the layout.
Worked example, not a result
The same page, read by a machine
Say a product page shows a price of 34.95, says the item is in stock, and displays a rating drawn from 48 reviews. A person reads all of that from the layout without thinking about it.
A machine has to guess unless the page states it. Schema markup states it explicitly: this is a product, this is its name, this is its brand, this is the price and currency, this is its availability, this is its rating and how many reviews it came from. The same page can carry more than one type of structured data, so it might also describe its breadcrumb trail and the organisation behind the store.
The rule that matters most is that the markup has to match what is visible. Marking up a price that differs from the displayed price, or a rating no shopper can see, is a policy problem rather than a shortcut, and it can remove a site's enhanced results entirely.
The figures are an example.
Why it matters
Structured data is how a store's facts travel beyond its own pages. Search results that show price, availability and ratings take more attention than plain links, and AI assistants answering shopping questions rely on being able to read facts confidently rather than parsing a design.
That makes it a cheap piece of visitors lever work with an unusually long life. Once the templates output correct markup, every product and collection published afterwards inherits it, including the ones nobody will ever optimise by hand.
It also enforces something useful internally. To mark up price, availability and delivery correctly, the page has to state them clearly in the first place, which is the same discipline that keeps product feeds accurate and stops shoppers arriving at prices that changed. For a store owner, that overlap makes structured data worth doing properly rather than approximately.
Common mistakes
- Marking up facts that are not visible on the page. Structured data is meant to describe what a shopper sees, and inventing values risks losing enhanced results altogether.
- Letting the markup go stale. A price or availability hard coded in a template keeps saying the same thing after the product changes.
- Adding it once per page by hand. Markup belongs in the template so every new product and collection carries it automatically.
- Never testing the output. Structured data fails silently, so a validation check after any theme change is the only way to know it still works.
Related terms and answers
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