Glossary · Internet & Web

URL Fragment (Hash)

A URL fragment is the part after the # symbol that points to a section within a page and is handled by the browser, never sent to the server.

Updated October 6, 2026

A URL fragment is the portion of a URL that follows #. It identifies a location inside the document, such as a heading with a matching id, and is processed only by the browser.

Why it matters

Fragments power in-page navigation and table-of-contents links. Single-page applications also use them for client-side routing. Because the server never receives the fragment, it does not appear in access logs and cannot be used for server-side decisions.

A practical tip: when you share a deep link to a section of a long guide, check that the target heading has a stable id, since automatically generated ids can change when a title is edited.

Example

https://example.com/guide#common-mistakes

The browser loads /guide and then scrolls to the element with id="common-mistakes".

Common mistakes

  • Expecting server-side code to read the fragment.
  • Linking to an anchor whose id was renamed, so the link silently lands at the top.
  • Using fragments for content that search engines need to index separately.

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