Modify Outgoing Request Header

Modify, add, remove, or pass along specific request headers going upstream towards the origin.

Why you need it

Use this behavior to decide how selected request headers going upstream towards the origin should be processed. For example, you can add headers such as User-Agent to inform the server about the user's browser, or use custom headers to control authorization. By controlling the content of your headers you can further customize your website visitor's experience and gain insight into how they use it.

How it works

When enabled, this behavior modifies the specified outgoing request header according to set rules.

Features and options

FieldWhat it doesSub-options
ActionSpecifies the action to perform on the header.
  • Add
  • Remove
  • Modify. This option replaces the entire value of the header.
  • Find & Replace. This option searches for a pattern in the header values and substitutes a pattern you specify.
Select Header NameSelect from standard pre-defined headers to modify.With Action set to Add, Modify or Find & Replace.
  • User-Agent
  • Other...


With Action set to Remove.
  • Pragma
  • User-Agent
  • Via
  • Other...
Header ValueWith Action set to Add, enter your HTTP header value.

Variable Support: This option supports variable expression syntax. Typing {{ in the option field triggers variable auto complete. Learn more about variable support.
Custom Header NameWith Select Header Name set to Other..., enter a custom HTTP header name.

Variable Support: This option supports variable expression syntax. Typing {{ in the option field triggers variable auto complete. Learn more about variable support.
New Header ValueWith Action set to Modify, enter your new HTTP header value.

Variable Support: This option supports variable expression syntax. Typing {{ in the option field triggers variable auto complete. Learn more about variable support.
Avoid Duplicate HeadersWith Action set to Modify, prevents multiple headers with the same name from being created.
Find WhatWith Action set to Find & Replace, finds a string matching the string you enter.

Variable Support: This option supports variable expression syntax. Typing {{ in the option field triggers variable auto complete. Learn more about variable support.
Replace WithWith Action set to Find & Replace, replaces the matched string with the string you enter.

Variable Support: This option supports variable expression syntax. Typing {{ in the option field triggers variable auto complete. Learn more about variable support.
OccurrencesWith Action set to Find & Replace, replaces only the first instance of the old value, or replaces every occurrence.
  • All
  • First occurrence only