Containers in Firefox – A Privacy Tool in this Brave New World of 2021

 In the dystopian societies we are living in, our lives are practically a cross between George Orwell’s novel 1984 and Brave New World by Aldous Huxley. Corporations and governments use all available technology to spy on citizens, they own the information media and power. At the same time, people are more and more conditioned with our daily Soma.

Aside from the relief of knowing that one day we’re all going to die (sorry, I’m in a nihilistic stage), Mozilla comes to the rescue once again to make our privacy a little less abused.

Since much of people’s lives are found on the Internet, our behavior is the raw material of corporations and governments that steal our data. By logging in to different social networks, we leave a trace that identifies us on different sites, and this information is available to the rest of the websites. Thus, when visiting sites of a topic, a social network that we visit frequently can show us ads and suggestions related to that topic that we visit without having contact (as far as we knew) with the social network in question.

In this way we generate a digital footprint that identifies us quite uniquely on the internet. This allows different sites to obtain information about us. To do the test, they can enter Your Social Media Fingerprint:

My Social Media footprint

In addition to revealing a vulnerability with this issue, we see that a public website knows which accounts we are logged into, which also reveals a lot of information about us. Without going into detail about the vulnerability (read more on the site), it is a good demonstration of a situation that should not be the case.

In particular, Facebook is quite good at knowing practically everything the user does on the internet. Although users choose not to be tracked, it even generates an identity from the browser and its cookies when the user logs out.
Containers to the rescue
Firefox Nightly

Firefox Nightly

One of the practices that I usually promote is to use several browsers on the same system for different browsing profiles. Even use Tor from time to time or for specific types of navigation (logging into Facebook being the ideal example). In this way we can try to keep the information a little less concentrated and give less data about our interactions with the internet.

In recent updates to Firefox Nightly, this problem with containers is specifically targeted. What the containers provide are different web browsing contexts. Each context has its own separate cookies, indexeddb, localStorage, and cache.

We can have a work browsing context on the one hand and social networks with our personal accounts on the other. In this way, we have the possibility of logging into the same social network with different accounts in parallel contexts, in the same browser window (or a new one), but in different tabs. Thus, we also segregate the information that we provide to each container, to obtain a little more privacy and security.

Another very common use case for web development is testing the site we are working on in a private browsing tab (incognito mode in Chrome) to have a zero cache and cookie set. Now we can even test different user profiles of our web applications simultaneously in different contexts within Firefox.

I personally use several different web browsers for different things. Generally, I don’t log into the same accounts in each one, I use each browser for different purposes. With Firefox Nightly this would no longer be necessary (that does not imply that I will stop using the other browsers, I have problems …).

By default we get 4 containers, but by accessing the privacy preferences of Firefox Nightly, we can customize them:

Firefox containers

Containers are seamlessly integrated into our daily navigation. Normal tabs are considered inside the container by default. We can open links in different containers or create new tabs from one of our containers. Advertiser tracking data, user sessions, and site preferences are not transferred to the new container. In turn, browsing within the container will not affect preferences, user sessions, or advertiser tracking data from other containers.

To open a link in a new container, it is a matter of right-clicking and choosing the container. Since Mozilla always thinks of us, it also added a handy icon to open a new container tab. I hope that eventually keyboard shortcuts can be assigned to “container X new tab”. For now we can only manage their names, color and icon.

Firefox containers menu

Using script

 tories in Linux, you could have a window of Work containers on the one hand, another of personal accounts on the other, etc.

Container tabs are identified with the name and color that we have assigned them:

Firefox Containers – Tabs

We can open the number of tabs of each container that we want. As far as I know, we can make infinite new containers (probably not true, but not finding information about it …).

An interesting idea that comes up on the Mozilla wiki is Site-Specific Containers. These would make a container assigned to a specific origin. For example a “Facebook Container” that is only used to isolate Facebook from the rest of the navigation. When a user enters “” in the address bar, he would receive a result that allows him to open the Facebook Container. The browser could also prevent or prompt the user to navigate to other sites within that container.

They could also prevent the user from navigating to a specific site outside of its container. For example, when navigating to “”, the browser might display a message: “Hey, you normally open this in a container, would you like to do that now?” with a button to close the tab and open the container.

These ideas are great, and I imagine that over time they will be implemented, as well as more configurations to the containers. They will eventually enter Firefox stable, but in the meantime I suggest downloading Firefox Nightly, which also feels quite a bit lighter than the current stable version on Debian.

In conclusion, another excellent contribution from Mozilla to its users when it comes to ensuring the privacy and security of its users. Is privacy a losing battle? It may be, but Mozilla hasn’t given up. These are the kind of cutting-edge features that other web browsers are likely to start implementing natively as well.

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