Header Tool


Using this tool you can easy modify headers on each HTTP call on the Mozilla Firefox. The tool is based on the same main stream idea of modify headers but use a more simple text editor interface more quicker do edit and to store and save for multiple and repeated test cases ( ie SCREENCAST ). As example you can save your header in a simple txt file and reuse it just cut (crtl+C) and pasting (crtl+V) it. With JAvascript support is easily to implement complex header calculation and for example put in place a Base Authentication mechanism using the built in function Base64 (b64) . If you find an issue or you have and idea on how improve it please open a ticket on this site, as soon as possible i'll try to fix it. If you are a developer don't hesitate to send to me the patch ;) The most simple way to add a set of custom headers is :

#this is a comment
x-header-example : thisIsThe.Value #this is an inline comment
x-header-example2 : an other text with spaces #this is an inline comment
x-header-example3 : text with %&£ $imbol$ #this is an inline comment

Since version 0.3.2 there is the support for JS substitution in ${} statement that permit you to do as example :

Authorization : Basic ${b64("username:password")} #implement Base authentication easily
X-USERNAME : ${window.btoa('foo')} #base64 encoding"
X-NOW : ${new Date()} #current date"
//split header def on multiple line

Fix : auto indentation and electric chars
Add: new syntax for regexp Header enable

Regular Expression Support

Since Version 0.3.6 You can use the "@" character at the first char in a line in order to specify a
regular expression set of header. Since this line all the headers comes above is
activated *only* for the matching URI.

x-all-0 : header-value //no @modification so is always enabled
x-all-1a : header-value //is taken in account only for server with serverURI_1
x-all-1b : header-value //is taken in account only for server with serverURI_1
x-all-2 : header-value //is taken in account only for server with serverURI_2

x-all-0 : header-value //no @modification so is always enabled
x-all-1 : header-value
@^https //the following two headers is enabled only for HTTPS
x-all-1a : header-value
x-all-1b : header-value
@prod //the following headers is enabled only for URI with "prod" inside
x-all-2 : header-value

Look at google code page for a full set of features manual.
Move from Modify Headers
If you are already using modify headers you can simply switch to this plugin just with the following steps :
  1. enable all the headers inside the modify headers (Enable All Button)
  2. open a site for header visualization ( http://headers.online)
  3. cut&past in the the header in the text area

Download files:


This page is part of the LegacyCollector website.
Disclaimer: All material on this site is property of their respective owners and available under
open licenses to the best of our knowledge. If you are an author and would like anything removed,
then please write an e-mail to legacy [at] collector dot org.