An add-on and web app for visualizing HTTP requests between websites in real time.
JavaScript HTML CSS Shell
Latest commit cfd7358 Jul 14, 2016 @fmarier fmarier committed on GitHub Merge pull request #712 from andymckay/mcp-flag
mark as multi process compatible

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.

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:

jpm 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 jpm run again.

Software Used

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