URL.

A URL can be broken down into parts. At the start is the protocol, today almost always https, which ensures an encrypted connection. Next comes the hostname, meaning the domain plus any subdomain. After that comes the path, which identifies a specific page, such as /services/web-design. Optionally, parameters follow after a question mark, such as ?utm_source=newsletter, which pass on additional information, and a fragment after a hash, which jumps to a position within the page.

The term URL is often confused with domain. The domain is only the name of the website; the URL is the exact address of a single piece of content within it. A website has one domain but as many URLs as it has pages, images and files. Each of these URLs can be linked, shared and indexed by search engines individually.

Descriptive URLs help search engines and visitors alike: short, lower-case, with hyphens instead of spaces and with words that describe the content. In German-language URLs, umlauts are best written out, i.e. ue instead of ü, because otherwise they appear in encoded form. Permanence matters just as much: a URL that changes loses its links and rankings if no redirect is set up.

Parameter URLs are a common cause of duplicate content. If the same page can be reached under several addresses, for example with and without filter parameters, a canonical tag should define which version is authoritative. How descriptive addresses are structured is explained under URL structure. In a website relaunch, matching old and new URLs is one of the most important steps, and status codes and redirects are among the checkpoints in a website audit.