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Use the extension to see why your privacy is in danger.

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What is Lightbeam?

Firefox logo Add-on for Mozilla Firefox (Installation)
Codeberg logo Open Source (Source Code)
Recording icon Records websites and third party requests
Graph icon Visualization


  • Recording of visited websites and their third party requests
  • Visualization of recorded data as a graph
  • Export of the recorded data
  • Fuse Mode: Fuse multiple third party requests into one node
  • All recorded data stays on your device
  • Languages: English and German

Latest News

New test version available (28. Mai 2024)

A new version of Lightbeam will probably be available in this summer. More details will follow when it will be released. If you can’t wait to see how it changed you can take a look at it in the beta version.

Lightbeam moves to Codeberg (28. November 2023)

Lightbeam is a tool which has the purpose (among others) to show that you need to protect your privacy. The add-on itself is also caring for your privacy and only saves recorded data local in your browser.

Gitlab which still hosts the repository of Lightbeam uses Cloudflare to protect its website from bots and Cloudflare makes it impossible to log in to the platform in some cases when you use a browser with add-ons that increase your privacy. That is the reason why I decided to move the repository of Lightbeam to a new home: Codeberg. Codeberg is maintained by a NGO and doesn’t use trackers, third party cookies or anything similar so it is the perfect place for Lightbeam.

There is already a repository for Lightbeam on Codeberg while the old one still exists on Gitlab. The plan is to replace all URLs on this website and in the add-on itself until the end of this year. Another todo is to create an archive of the old repo and leave a note so everyone knows that the development is taking place on Codeberg.

New Release: Lightbeam 2.4.0 (6. September 2023)

Some persons shared useful ideas how to improve Lightbeam on Gitlab and this release contains these improvements.

You can now filter the first parties by choosing different options in a new sidebar. These options affect which first party websites are shown. So if you decide to show only 50 websites this means that Lightbeam shows only 50 first party websites. Because first parties may contain a different number of third parties the graph could contain much more than 50 nodes. It would be technically possible to limit the nodes to a specific number but this would cost more performance, so I decided not to do so.

The drawing of the graph is an ressouce-intense process. If you recorded many websites it could even be that Lightbeam crashes. That’s why Lightbeam now shows a warning when there are more than 200 nodes.

Additionally to these changes there are more features. With the newest version it is possible to import data that you exported before. This is not only helpful to make testing of Lightbeam easier. It also gives you the opportunity to prepare some special cases that you can just import at every time and show to other people.

And there are other little changes:

  • Data can also be saved in a fused version.
  • Export contains metadata (e.g. version of Lightbeam used to export the data).
  • Only “real” third parties are shown (before also URLs like abc.domain.de were shown as third parties when they were called from domain.de although they aren’t third parties in this case).
  • The tooltip shows the number of requests.

Why you should try Lightbeam

People who use a browser without any extensions often don’t have a clue what’s going on while they are browsing through the web. They don’t know that these websites are contacting other servers for additional ressources, tracking etc.

Lightbeam can show them that many websites make requests to the same third party and that some third parties - like Google - are present on the majority of all websites. This leads to the insight that those third parties know which websites you are visiting. What they do with this knowlegde - or data - is a different thing.

A little background


The history began as developers from Mozilla developed an add-on named Collusion. Interested people can find out in the source code that the development started on the 29th of July 2011. The first time Mozilla published its add-on was 2017. Since the technology inside of internet browsers changed over the years it was necessary to rebuild the add-on which was renamed to Lightbeam in the meantime. For this reason a different repository became the new home for Lightbeam (Github). Two years later the last contribution was made until the source code should stay untouched for the time being (Announcement by Mozilla).

The consequence was that Mozilla didn’t offer the add-on on add-ons.mozilla.org (AMO) anymore. This fact reached my - Christoph Klassen - ears when people at Digitalcourage talked about it. Since some of them used that add-on to show others what happens in the background while they are surfing in the internet I decided to revive Lightbeam.


One main goal is that people can use Lightbeam further. That means that I adjust it as soon as conditions for add-ons are changed by Mozilla. Otherwise Mozilla would throw Lightbeam out from AMO. The next main goal is to keep it up-to-date on the technical side so I will update the libraries, replace deprecated methods and so on.

New features don’t belong to the most important goals but few people requested new features and I implemented them because they are useful additions to the add-on. The fuse mode is one of those features. As long as there are only requests every now and then I will keep integrating new things into Lightbeam. Please don’t hesitate to create an issue on Codeberg or to write an email to me about your ideas!

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