A URL (Uniform Resource Locator) identifies the location of a resource and how to access it. Joomla uses URLs for pages, images, downloads and requests to web services.
Parts of a URL
In https://example.com/catalog/item?color=blue#details, the https scheme identifies the protocol, example.com is the host, /catalog/item is the path, ?color=blue is the query and #details is the fragment. Not every URL contains every part. A port can appear between the host and the path.
The fragment is normally handled by the browser and is not sent to the server in the HTTP request. Query parameters are sent and may change a filter, sorting order or response content. Spaces and other special characters require URL encoding. Letter case in a path can matter.
Absolute and relative references
An absolute URL includes a scheme and host. The browser resolves a relative reference against the document base URL. A path such as /glossary/terms starts at the current site root, while images/photo.webp depends on the base path.
URLs in Joomla
Joomla routing converts component parameters into page addresses. Menu items, languages, aliases and SEF settings affect the result. An article alias is only one part of an address and does not necessarily determine its complete URL.
After changing Joomla routes, check internal links, redirects and canonical URLs. Avoid putting passwords, secret keys or personal information in query strings, because URLs can appear in browsing history and logs.
Conclusion
Understanding URL components helps create stable links and diagnose navigation problems.