A URL alias is just an alternate URL that will load an internal Backdrop URL.For example, if the post at URL "node/61" can also be accessed at the URL "about-dragons" then "about-dragons" is an alias of "node/61".A URL (Uniform Resource Locator) is essentially the generic term for web addresses, meaning the link in the address bar of your browser, such as To access content on a Backdrop site, users need a URL to find it, so every content item is given an internal URL in the format "Entity Type/Entity ID", leading to URLs for your content and users like or or Patterns are generated using wildcards called tokens to extract elements of the entity which can be then used for creating the URL alias.
This way, your site is more user and search engine friendly, and more descriptive about its content with less work from your side.
To do so, Backdrop requires that you provide patterns to set how your aliases are generated.
The aliases are generated when you create an object in your site.
These, however, are not friendly or easy to remember; it would be much better to have readable addresses like or
Therefore Backdrop's built-in Path module allows you to automatically override those default internal URLs with URL aliases based on simple rules.Therefore if you set the pattern for Page content to be "my-pages/[node:title]", the alias for the node mentioned in the previous paragraph would become "my-pages/about-dragons".