---
title: Rules language · Cloudflare Ruleset Engine docs
description: 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.
lastUpdated: 2024-09-06T15:21:19.000Z
chatbotDeprioritize: false
source_url:
  html: https://developers.cloudflare.com/ruleset-engine/rules-language/
  md: https://developers.cloudflare.com/ruleset-engine/rules-language/index.md
---

The Cloudflare Rules language is a flexible and intuitive specification for building rule expressions. Based on the widely known [Wireshark display filters](https://www.wireshark.org/docs/wsug_html_chunked/ChWorkBuildDisplayFilterSection.html), the Rules language allows you to precisely target HTTP requests with a syntax and semantics familiar to security engineers.

Refer to the following pages for more information about the available language elements:

* [Expressions](https://developers.cloudflare.com/ruleset-engine/rules-language/expressions/)
* [Operators and grouping symbols](https://developers.cloudflare.com/ruleset-engine/rules-language/operators/)
* [Values](https://developers.cloudflare.com/ruleset-engine/rules-language/values/)
* [Actions](https://developers.cloudflare.com/ruleset-engine/rules-language/actions/)
* [Fields](https://developers.cloudflare.com/ruleset-engine/rules-language/fields/)
* [Functions](https://developers.cloudflare.com/ruleset-engine/rules-language/functions/)
