Overview
About
Phases
Rulesets
Rules
Basic API operations
View rulesets
Add rules to phase entry point rulesets
Deploy rulesets
Work with managed rulesets
Deploy a managed ruleset
Override a managed ruleset
Override examples
Set WordPress rules to Block
Enable only Joomla rules
Enable only selected rules
Deploy a managed ruleset with ruleset, tag, and rule overrides
Adjust the sensitivity of an HTTP DDoS rule to Low
Adjust an L3/4 DDoS rule
Work with custom rulesets
Create a custom ruleset
Add rules to a custom ruleset
Deploy a custom ruleset
Rules language
Expressions
Operators and grouping symbols
Values
Actions
Fields
Functions
Rulesets API
JSON object
Endpoints
List and view rulesets
Create ruleset
Update and deploy rulesets
Add rule to ruleset
Update a rule in a ruleset
Delete a rule in a ruleset
Delete rulesets
Reference
Phases list

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.