Firefox Containers let you categorize your browsing activity and compartmentalize cookies and other browser storage. Essentially, they stop websites from tracking your web browsing, preventing them from seeking anything outside their own container and following you around. It's a great alternative to deleting your cookies and cache, or refusing cookies, which can break some websites or cause them to not work properly.
How to Install Firefox Containers
Containers are an add-on for Firefox. You can install them like any other.
Open Firefox, and head over to the Containers add-on page. Select Add to Firefox to download the add-on.
Firefox will ask you to confirm the install. Select Add.
It'll take a few seconds for the install to complete. Afterwards, you should see a new icon in your Firefox menu for containers.
How to Use a Firefox Container
Using Containers is very simple. Choose a container type, browse to a website, and tell Firefox to always open that website in the container you're using.
Open Firefox and select the Containers icon in the upper-right corner of your window.
In the menu that appears, select one of the container types: Personal, Work, Banking, or Shopping.
In the new tab that opens for your container, browse to the website you want to confine to that container.
Select the Container icon a second time, and select Always open in.
Try browsing to the website in a different tab. Firefox will prompt you to open it in the container you set up. Select the appropriate container to do so.
How to Create Your Own Firefox Container Types
You can make your own container types. Whether you want to make website-specific ones or create new categories, you can do whatever you need.
Select the Containers icon.
Select the + icon in the lower-right corner of the menu.
Enter a name for your container type, then pick a color and icon.
Select OK to save your new container type.
Back on the listing, you'll see the new container type listed with the default container types.
How to Use the Firefox Facebook Containers
Facebook containers are another type of container Mozilla specifically designed to automatically contain Facebook and all other websites under its control.
Open Firefox, and go to the Facebook Container add-on page. Select Add to Firefox to install the add-on.
Select Add to confirm the installation.
After the installation, open Facebook. It will automatically convert to a Facebook container.