---
title: Headers
description: Using request matchers to specify which requests should respond. TODO
---

This section describes matcher functions designed to target and match HTTP headers in incoming HTTP requests.

## header
{{{docs.when.header}}}

## header_not
{{{docs.when.header_not}}}

## header_exists
{{{docs.when.header_exists}}}

## header_missing
{{{docs.when.header_missing}}}

## header_includes
{{{docs.when.header_includes}}}

## header_excludes
{{{docs.when.header_excludes}}}

## header_prefix
{{{docs.when.header_prefix}}}

## header_prefix_not
{{{docs.when.header_prefix_not}}}

## header_suffix
{{{docs.when.header_suffix}}}

## header_suffix_not
{{{docs.when.header_suffix_not}}}

## header_matches
{{{docs.when.header_matches}}}

## header_count
{{{docs.when.header_count}}}