This tag is very broad, try being more specific by using tags relevant to your problem. Examples are "rule-engine" for rules engines, "url-rewriting"/"mod-rewrite" for rewrite rules or "form-validation" for validation rules. See the full wiki article for a more complete list.

Rules are used to describe a requirement for data or behavior in software.

If a more specific tag exists for the subject of your question, please use that tag to better contact experts familiar with that technology.