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Rules language

The Cloudflare Rules language is a flexible and intuitive specification for building rule expressions. Based on the widely known Wireshark display filters, the Rules language allows you to precisely target HTTP requests with a syntax and semantics familiar to security engineers.

When evaluating a rule, Cloudflare compares values associated with an HTTP request to those defined in the rule's expression. If the expression evaluates true, Cloudflare triggers the action for that rule.