200 reviews
  • This is a fantastic add-on for users who are concerned about privacy while surfing the web because it efficiently detects and blocks/fakes canvas fingerprinting. I use CB on all my machines with Firefox (52-ESR and >57) and it supplements nicely other privacy-related add-ons. Based on my own experience, I can also confirm that it receives superb support by a very helpful and responsive developer. Clearly a must-have five-star addon!
  • Funktioniert bei richtiger Einstellung korrekt. Schneller support. Danke!

    Works fine if settings are correct. Fast response. Thanks!
    I will look into this issue (progress can be seen here: https://github.com/kkapsner/CanvasBlocker/issues/161). The faking is working fine on https://browserleaks.com/canvas

    EDIT: They are using a very big canvas (400 000 pixels) to do the fingerprinting. It works fine if you disable the "Maximal fake size" ("Maximale Vortäuschgröße") setting. I will adjust the recommendation accordingly.
  • Very configurable and useful tool if you don't want to be easily fingerprinted. In 1000 years it will be common knowledge to install in every Firefox. For now, we're the lucky ones that learned about it.
  • Seems to cause issues with direct links to images. When this addon is activated only a white page is displayed instead when the domain is loaded for the first time. Deactivating the addon and reloading the link makes the image show up correctly. Afterwards the addon can be re-enabled again without making the image disappear again (only lasts for the session, restarting firefox breaks it again).
    FF ESR 52.5.0

    The issue has been resolved, the author created a separate version. Great support!
    This issue was already reported to me. But I'm not able to reproduce it on my end. Please create a new issue on github with the informations to reproduce the problem (Firefox version, installed Addons, CB settings, URL to the not working image and if the problem is still present when a fresh profile is used): https://github.com/kkapsner/CanvasBlocker/issues/new
  • 本質的です
  • Thanks!
  • Great add-on.
  • es debe tener
  • Awesome add-on
  • Great extension, I really like the look of the icon in the address bar.
  • Apologies, but this is an honest question: What would be the purpose of the add-on having access to 'all website data' such as banking/email login information?
    You can look at the code (either at https://github.com/kkapsner/CanvasBlocker/ of you can download the xpi-file, change the extension to zip and look at the content). It does not store any private information or sends anything to a server.
  • Very good add-on
    It would be bery nice if this great add-on also could portect against font fingerprinting.
  • .
  • Отлично работает ;>
    Спасибо Разработчикам>
  • @ kkapsner

    Please check the link below:


    is positive for Canvas Defender and ScriptSafe for Chrome.
    With CanvasBlocker the icon briefly appears and disappears immediately.


    Unable to view single images.
    I can insert some links but privately.
    Thanks for your finding. The faking is working fine - just the display of the icon is confused by this site. This will be fixed in the next release (see https://github.com/kkapsner/CanvasBlocker/issues/149 for reference - btw it's much easier for us to communicate on github via issues than AMO)

    Since this is a minor issue there will not be a release for this alone.
  • can't get the add on CavasBlocker on the new quantum version beta.Keeps telling me I'm running version 54.0???
    Please recheck your Firefox version and try to add it again. Version 0.4.2 should also run with Firefox 52.4.1
  • Thanks for creating this, kkapsner. Super helpful.