I recently wrote a tiny Chrome extension to remove document.interestCohort() from every page so that a website cannot query your browser for its cohort ID.


So I could call it FLoC Block FLoC, short for Federated Learning of Cohorts, is the new mechanism used by Google Chrome to group users into buckets based on their interests. You can read more about it here and why Brave and some other browsers have blocked it here. EFF did some analysis as well.

How does this Chrome Extension help?

If you HAVE to use Chrome but don’t like the idea of being grouped into a bucket (aka cohort) based on the websites you visit, this extension is a simple way to prevent FLoC from divulging your “cohort id” to websites. The extension removes document.interestCohort() from every page so that a website cannot get your cohort id.

How do I install this extension?

From Chrome Web Store


From GitHub

  1. Download flocblock.zip from https://github.com/ShivanKaul/flocblock/releases/latest. Direct zip download link.
  2. Extract extension.
  3. Follow the instructions to load into Chrome.

How do I verify that the extension is working?

After installation, https://amifloced.org should say that your browser does not have FLoC enabled.


git clone https://github.com/ShivanKaul/flocblock.git
cd flocblock
npm install # to install browserify.
npm run build # to build the extension. 
npm run pkg # to create a .zip

To setup FLoC locally

Follow the instructions at https://floc.glitch.me