---
title: Reference
description: Reference for response header modification rules.
image: https://developers.cloudflare.com/core-services-preview.png
---

> Documentation Index  
> Fetch the complete documentation index at: https://developers.cloudflare.com/rules/llms.txt  
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# Reference

This section contains reference information for Response Header Transform Rules.

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

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