---
title: Reference · Cloudflare Rules docs
description: This section contains reference information for Request Header Transform Rules.
lastUpdated: 2025-04-15T11:19:33.000Z
chatbotDeprioritize: true
source_url:
  html: https://developers.cloudflare.com/rules/transform/request-header-modification/reference/
  md: https://developers.cloudflare.com/rules/transform/request-header-modification/reference/index.md
---

This section contains reference information for Request Header Transform Rules.

* [Format of HTTP request header names and values](https://developers.cloudflare.com/rules/transform/request-header-modification/reference/header-format/)
* [Available fields and functions](https://developers.cloudflare.com/rules/transform/request-header-modification/reference/fields-functions/)
* [API parameter reference](https://developers.cloudflare.com/rules/transform/request-header-modification/reference/parameters/)
