A Dirty URL is a URL (web address) that contains a question mark, followed by parameters. For example:
Dirty URLs are sometimes required for web applications, but are considered bad practice for the majority of normal content pages which rarely require them.
Why are Dirty URLs bad?
- Humans can’t easily type them, or remember them. Try reading out the web address above to someone over the phone.
- Search engines often ignore them. Or rank pages with query parameters as lower. Either way, this is bad for your SEO.
- They expose parameters to the outside world. Poorly implemented, query parameters expose aspects of your web technology to the outside world. They can be perfectly secure, but removing unnecessary use makes securing your sites easier.
Dirty URLs are detected and penalized for by the URL format test.