The latest update to Firefox Nightly has enabled the Container tab feature. This is part of Mozilla’s context identify project, still in draft phase, but has been implemented initially in Nightly for testing to validate.

What are containers?’

According to official project page, these are ‘Lightweight persistent profiles that isolates sites from one another’. Want to browse  social networking sites and work sites without one site knowing the other. Containers are for that purpose.

“The goal of this project is to allow users to separate these different contexts while browsing the web on Firefox. Each context will have its own local state which is separated from the state of other contexts.”

container tabs

Sites opened and viewed in one Container doesn’t know what other sites you’re viewing in another. You can open a container tab from File menu as well hamburger menu.

Open container tab

Difference between container tabs and normal tabs

“Container tabs operate just as you would expect a normal tab to, except for the fact that the sites you visit will have access to a separate slice of the browser’s storage. This means your site preferences, logged in sessions, and advertising tracking data won’t carry over to the new container. Likewise, any browsing you do within the new container will not affect the preferences, logged in sessions, or tracking data of your other containers.”

Mozilla has included these containers in Nightly

  • Personal (to use at home)
  • Work (to use at office)
  • Banking (for accessing sites with financial or sensitive information)
  • Shopping (for accessing eCommerce sites)


You can use different containers for different purposes. For e.g. you can sign into email accounts and social accounts on personal and work containers. Use shopping container to browser shopping sites, and you can sign into banking sites to access financial information by using the banking container.

Currently, the following data is separated between the containers

  • Cookies
  • localStorage
  • indexedDB
  • HTTP data cache
  • Image Cache

You can disable containers by toggling privacy.userContext.enabled`preference value to ‘false‘ in about:config, set to true to enable it.

Container tabs or tab container concept does take a while to understand and it’s a bit confusing as well. Head over to this page  and Mozilla blog post for more information.

Update: Containers is an experimental Nightly only feature and is no going to ride the trains.