You can find this feature in the "URL Rewrite" tab of a site's configuration.
This feature can be useful to simplify URLs that are too complex for your users.
Destination path is a RE2 regular expression.
Rewrite rules are all applied in sequence.
Simple use :
Example: reduce /foo-admin-bar to /admin :
With this rule, www.my-website.com/admin will return - without redirection - the content of the page www.my-website.com/foo-admin-bar
Advanced use with capture group :
You can use capture groups (regular expression in brackets) to capture fragments of URLs and order them as you want:
Here, the $1 will be substitute by the first capture group (.*).
You can test it in the tester :
Identify a rewrite rule in "My Logs":
In "My Logs", you can find a request that has matched a rewrite by an "R" badge.
Don't forget to activate the rule with the toggle button!