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Glossary Metadata

What Is Metadata?

Manuel Riveiro Rodriguez
Manuel Riveiro Rodriguez

CEO & Digital Strategist

5 min reviewed on 2026-10-14

  • SEO On-Page
Definition

Metadata is data that describes other data. On a web page, it is the information about the page itself, such as its title, description, language or author. It is not part of the visible text, but search engines, social networks and browsers read it.

On this page 5
  1. What metadata means
  2. How it works
  3. Why it matters
  4. Best practices
  5. Common mistakes
In brief

Metadata is data about data: on a website, the information about a page that search engines, social networks and browsers read.

What metadata means

The prefix "meta" signals information about something rather than the content itself. A library catalogue card is the classic example: author, year and subject describe the book without being the book. A digital photo stores similar metadata, such as the date, the camera or the location.

On a web page, most metadata sits in the head of the HTML, the part the browser does not display as content. That is where you find the title, the meta tags, the canonical tag, the hreflang references to other languages and, increasingly, structured data in JSON-LD.

How it works

Each type of metadata has its own audience. Google defines meta tags as HTML tags that give search engines and other clients additional information about a page, and it publishes the list of those it understands: among others, description, robots, google-site-verification, charset and viewport. Tags it does not support, it ignores.

Social networks read a different set of metadata. Open Graph tags, which start with og, set the title, description and image that appear when a link is shared. Structured data, for its part, describes what the page is in a shared vocabulary, for example an article, a frequently asked question or a product.

Having a piece of metadata does not guarantee that it is used. Google says it creates the snippets in its results primarily from the page content, and that it uses the meta description when it describes the page better than other parts of the text. The keywords meta tag, on the other hand, it does not use at all.

Checking the snippet in Google tells you nothing about the share preview.

Why it matters

Metadata decides how a page presents itself before anyone visits it. The title and meta description influence what appears in search results, Open Graph tags the preview in social networks and messaging apps, and the canonical and hreflang which version of a page reaches the index and which audience sees it.

It can also cost visibility. A robots tag with noindex removes a page from the results, and a canonical pointing to the wrong URL can make the search engine index a different version. That is why metadata deserves the same care as the text.

We measured this on this glossary's entry about HTML on 13 October 2026. Its head contains a title, 15 meta tags, a canonical, four hreflang references and two blocks of structured data; a third sits in the body of the page. Of the 15 meta tags, two are aimed at search, the description and robots, one verifies ownership of the site in Search Console, nine serve the preview on social networks and three are for the browser or purely informational.

Best practices

  • Write a title and meta description of their own for each page that sum up what it offers.
  • Check that the canonical points to the URL that should be indexed.
  • Declare language versions with hreflang, with each one linking to all the others.
  • Add Open Graph tags with an image designed for the preview.
  • Use structured data that describes what is really on the page.
  • Review the head in the source code, not only through what a plugin shows.

Common mistakes

  • Repeating the same title and description across many pages.
  • Leaving a noindex from a staging environment in place at launch.
  • Filling in the keywords meta tag, which Google does not use.
  • Marking up content with structured data that does not appear on the page.
  • Expecting the meta description always to appear unchanged in the results.
Manuel Riveiro Rodriguez CEO & Digital Strategist

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Frequently asked

What is the metadata of a web page?

It is the information about the page that is not part of the visible text: the title, the description, the robots tag, the canonical, the language, the tags for social networks and structured data. Most of it sits in the HTML head, and search engines, social networks and browsers read it. Visitors usually see only the title, in the browser tab.

Which metadata does Google use?

Google publishes a list of the meta tags it understands, including description, robots, google-site-verification, charset and viewport, and it ignores the rest. It also reads the title, the canonical, hreflang and structured data. It does not use the keywords meta tag for indexing or ranking.

Does Google always show my meta description?

Not always. Google says it creates snippets primarily from the page content and uses the meta description when it describes the page better than other parts of the text. A precise description that is different on every page makes it more likely that Google will use it.

What is the difference between metadata and structured data?

Structured data is one kind of metadata. Whereas a meta tag gives a single piece of information, such as the description, structured data describes the page in a shared vocabulary, usually Schema.org, saying for example that it is an article with an author and a date.

Do photos have metadata too?

Yes. Cameras and phones store details such as the date, the camera model and sometimes the location in each file, in a format called EXIF. It is worth checking them before publishing images, especially if they reveal the location of a home or a client.