Multi-Account Containers is a Firefox add-on that lets you separate your work, shopping, or personal browsing without having to clear your history, log in and out, or use multiple browsers. It's an improved version of the Containers feature built into Firefox Nightly and available to advanced users by setting certain preferences (see below).

What are Containers?

Container tabs are like normal tabs however 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 your logged in sessions, or tracking data of your other containers.With the Firefox Multi-Account Containers extension, you can:

Privacy in Firefox Multi-Account Containers

The Firefox Multi-Account Containers extension does not send any information to Mozilla.

How to use Multi-Account Containers

1. Install the Firefox Multi-Account Containers extension from the Mozilla Add-ons website. To open Containers, look for the Containers icon in the Firefox toolbar:

   

2. Click on it and select the container you want to open.

   

You can open new Container tabs and each one will keep separate browser storage (such as cookies or localStorage) from other Containers. Your normal tabs are the default container and will still look and act as you'd expect them to before enabling containers.

You can open the Container Tabs settings panel as follows:

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. In the General panel, go to the Tabs section.
3. Click the Settings… button next to Enable Container Tabs.

Open links in new tabs and containers

You can open links in a new or different container. Right-click on any link, select Open link in New Container Tab, and then select the desired container.

If the current page is in a container, the Open link in New Tab item changes to Open link in New ContainerName Tab. Click on it to open a new tab within the same container as the previous tab.

What you can do with Multi-Account Containers

1. Log in to multiple accounts on a single website at the same time. For example, if you have a personal Gmail account and a work Gmail account, you can log in to both accounts in separate containers.
2. Protect yourself against tracking without having to log out of websites while you browse. Websites in one container can't track your activity in other containers.
3. Protect yourself against Web security attacks. Any harmful clicks will be kept within that website's container, so attackers won't be able to hijack your information in other containers.
4. Assign a website to a container, so that a specific website will always open in a specific container. This helps protect from accidents, stopping you from accidentally visiting a shopping site in your banking container, for example.
5. Hide and Show: If you use your browser for both Work and Personal tasks and don’t want to be thinking about “Work” when you come home, you can “Hide” your Work tabs and proceed with your Personal tasks. Then the next day, when you are back at work, you can “Hide” your Personal tabs and “Show” your Work tabs.
6. Sort: The Container Menu has a “Sort Tabs” option and a “Move tabs to a new window” option. Sort Tabs will put all your tabs of the same container type next to each other in a given browser window. So if you have “Work” and “Personal” tabs interleaved within each other, you can easily sort them to help organize your tasks (as seen below). “Move tabs to a new window” will take all the container tabs in your current window and move them to a fresh window.
7. The sync feature will align Multi-Account Containers on different computers. The add-on carries over Container names, colors, icons, and site assignments on to any other machines with the same Firefox account.
8. Avoid leaving social-network footprints all over the web (for example, you could use a Container tab for signing in to a social network, and use a different tab for visiting online news sites, keeping your social identity separate from tracking scripts on news sites)

For advanced users

You can also enable Containers without the Multi-Account Containers extension, by changing some preferences in the Configuration Editor (about:config page). Note that you will get a better user experience by installing the extension but, if you choose not to, you can set privacy.userContext.enabled to true and privacy.userContext.ui.enabled to true in about:config. You can open the Container menu via a right-click or via a long left-click on the plus sign + button. See also privacy.userContext.newTabContainerOnLeftClick.enabled in about:config to set the left-click behavior whether to open the Container menu or a New Tab.

How does this compare to the Facebook Container extension?

Facebook Container specifically isolates Facebook and works automatically. The Firefox Multi-Account Containers is a more general extension that allows you to create containers and determine which sites open in each container. This extension can be customized to suit your needs for multiple sites and multiple logins, but takes more time to set up than Facebook Container.

You can use Multi-Account Containers to create a container for Facebook and assign facebook.com to it. Multi-Account Containers will then make sure to only open facebook.com in the Facebook Container. However, unlike Facebook Container, Multi-Account Containers doesn’t prevent you from opening non-Facebook sites in your Facebook Container. So users of Multi-Account Containers need to take a bit extra care to make sure they leave the Facebook Container when navigating to other sites. In addition, Facebook Container assigns some Facebook-owned sites like Instagram and Messenger to the Facebook Container. With Multi-Account Containers, you will have to assign these in addition to facebook.com.

Facebook Container also deletes Facebook cookies from your other containers on install and when you restart the browser, to clean up any potential Facebook trackers. Multi-Account Containers does not do that for you.

Can I use both Multi-Account Containers and Facebook Container?

Yes, but you need to be a little careful. Don't use Multi-Account Container to assign facebook.com to a Container, and then try installing Facebook Container. If you a Multi-Account Containers user and want to use both addons, unassign facebook.com, messenger.com, and instagram.com first, then install Facebook Container.