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An add-on and web app for visualizing HTTP requests between websites in real time.
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Lightbeam for Firefox README

This is an add-on for Firefox that helps to visualize sites that may be tracking you around the internet. The add-on is available from


If you only want to see the demo, you don't need any of these; all you need is a modern browser.

Quick Start

First, install the Mozilla Add-on SDK if you haven't already, and activate it in a command line terminal.

cd addon-sdk
source bin/activate

Then, check out the Lightbeam repository and enter it (do this where you want the lightbeam directory, not in the addon-sdk directory):

git clone git://
cd lightbeam

Finally, run:

cfx run

This will start Firefox with a temporary profile that has Lightbeam installed. Just click on the Lightbeam icon at the bottom-right of the browser window to open the web front-end.

At this point, any changes you make to the web front-end simply require reloading the tab containing it. Changing the add-on, however, will require quitting Firefox and running cfx run again.

Software Used

The following software is bundled with the repository and doesn't need to be manually obtained.

Data Used

Contained within the repository is a JSON file listing all public trackers on the internet. It came with the TrackerBlock add-on.


All files that are part of this project are covered by the following license, except where explicitly noted.

Version: MPL 1.1/GPL 2.0/LGPL 2.1

The contents of this file are subject to the Mozilla Public License Version
1.1 (the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at

Software distributed under the License is distributed on an "AS IS" basis,
WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
for the specific language governing rights and limitations under the

The Original Code is collusion.

The Initial Developer of the Original Code is the Mozilla Foundation.

Portions created by the Initial Developer are Copyright (C) 2010
the Initial Developer. All Rights Reserved.


Alternatively, the contents of this file may be used under the terms of
either the GNU General Public License Version 2 or later (the "GPL"), or
the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of either the GPL or the LGPL, and not to allow others to
use your version of this file under the terms of the MPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the MPL, the GPL or the LGPL.
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