Firefox Containers Preview

7/21/2026 at 6:11:49 PM

I’ve been using Firefox Containers for years through Mozilla’s Multi-Account Containers extension.[1] Now that container management is available directly in Firefox, I’d prefer to use the native implementation if possible.

Mozilla notes that the extension still adds some functionality:

> “Installing the Multi-Account Containers extension developed by Mozilla provides a few benefits on top of the native container functionality like site-specific container assignments, syncing across devices, and integration with Mozilla VPN or your own proxy.”[2]

I don’t currently need any of those additional features, so the native version would probably be enough for me. What I haven’t been able to figure out is how to switch without losing my existing setup. Are the containers created by the extension already shared with Firefox’s native container manager, or is there some migration process? Can I safely uninstall the extension and keep my existing containers, names, colors, icons, cookies, and active sessions?

[1] https://addons.mozilla.org/en-US/firefox/addon/multi-account...

[2] https://support.mozilla.org/en-US/kb/how-use-firefox-contain...

by pentagrama

7/21/2026 at 7:46:15 PM

> Can I safely uninstall the extension and keep my existing containers, names, colors, icons, cookies, and active sessions?

Great question.

As a very satisfied, long time user of 2 extensions in combination, Temporary Containers and Firefox Multi-Account Containers, I wonder the same thing.

I found out the hard way some time back that simply disabling (not even removing it) and re-enabling the Firefox Multi-Account Containers extension would cause all the painstakingly set up containers and their saved credentials/data to get "lost".

If there were to be a way to "export" and "import" sets of named containers with their settings and data, that would be great for not losing which-site-maps-to-which-container-and-is-already-signed-in (whether natively or within an extension).

by realityfactchex

7/21/2026 at 6:45:20 PM

Back in like 2017? or 2018 when Containers came out for Firefox, I used the Multi-Account Containers Extension to manage QA testing of web apps, I'd have a container labeled for the user I wanted to log in as and test. It's insanely useful for the web.

What's also interesting is Tor Browser could probably take full advantage of containers later on, but I'm not sure if they would come up with a specific way of using it or just disable it.

by giancarlostoro

7/21/2026 at 7:06:43 PM

> site-specific container assignments

This is (or was, before I switched to Vivaldi) the killer feature of Firefox containers for me. I could banish certain tracking-heavy sites to their own containers so that they could only track where I've been on their own properties and not across the whole web. (Without having to remember to switch to their containers beforehand.) So I guess if I go back to Firefox, I'll still have to use the extension.

And maybe I'm misremembering, but I thought that containers did more than just separate the cookie jars? I really like using Vivaldi/Chrome's separate profiles because then I can have separate extensions/settings/polices/etc for each one. Some sites don't get along with certain extensions.

by bityard

7/21/2026 at 7:06:37 PM

Good that they are integrating that into the main browser.

For me the big use case is having different Google accounts active in one window. Work and private. And when I was doing freelance projects, I sometimes had 3 or 4 different Google accounts active. Plus assorted stuff tied to those accounts. Using different colors for each makes it easy to tell apart the tabs.

Another use case is if you are testing the same app for different customers with different credentials. I do this a lot and I have dedicated containers for each customer so I can easily switch with out having to log out and in a lot.

And of course some companies that can't be trusted with cookies, like Facebook, get isolated. I open that container less and less these days. But I still check every few months. I also keep my bank's website in its own container just on principle.

by jillesvangurp

7/21/2026 at 7:16:48 PM

If seems this should make obsolete the setup of having a separate computer (e.g., old laptop) to isolate Facebook properties, or am I missing something where a separate machine would be advantageous?

(I avoid FB like the plague but may need to use it for some biz uses where they effectively host too large a share of the intended market)

by toss1

7/21/2026 at 9:10:02 PM

Depends. Either you need to guard against e.g. fingerprinting the GPU, in which case you still need a separate machine, or you only need simple separation of cookies and the like, in which case you never needed that and could just use separate browser profiles. But yeah, I think in the latter case containers should work, though if it matters you should double check what exactly they do and don't separate.

by yjftsjthsd-h

7/21/2026 at 6:19:44 PM

Firefox's Multi-Account Containers changed the game for me back in 2018 or 2019, and is what got me to switch back to Firefox for 95% of my personal browser use. The "Always open {{domain}} in this container" and the ability to open a specific container with a keyboard shortcut seem like small things, but I can't imagine life without them anymore.

I never understood why it was set off to the side in an (official, first-party) extension, because I was always afraid they would one day stop supporting it. Now when I explain to people why I prefer Firefox, I don't have to explain "There's this extension, don't worry it's official, that allows me to..." I can just say "It has containers built-in. They're great. Try them."

by chao-

7/21/2026 at 6:31:26 PM

Yep, same here

MAC + Temporary Containers extension is how web browsing should be handled by default imo

No website deserves permanence of any data in my browser unless I so choose

I haven't seen similar functionality in any of the new generation of browsers, nor any of the Firefox spinoffs as-yet

by waz0wski

7/21/2026 at 7:27:12 PM

I use profiles for this, I wonder what the tradeoffs are between the two approaches. I've actually been thinking about building some tools to make it easier to create and manage profiles on the fly. For me I really think profiles are better since the boundaries are harder - there's no worry about accidentally hitting the "log in with Google" button and clearly identifying myself to a site or similar, because I read the news in a separate profile from my Google account. And it would be nice if those sort of guardrails were very intuitive and easy to set up by default. But I feel like containers may be too squishy.

by lukeschlather

7/21/2026 at 8:47:48 PM

[dead]

by HackerThemAll

7/21/2026 at 10:11:46 PM

This is not new, and it's really weird that Mozilla are not acknowledging that.

I just created a new profile in Firefox 140 ESR, started it in safe mode (which disables extensions), enabled "privacy.userContext.enabled" in about:config - and there you go, native containers accessible from File -> New Container Tab.

I'm not talking about the Multi-Account Containers extension. There are no extensions installed or enabled. It comes with Firefox 140 ESR, without extensions.

The Containers feature is already a "native, first-party feature" in older versions of Firefox. Firefox already has a "first-party version of containers". They have already brought it "directly into the heart of Firefox for all to benefit".

What are they talking about? Are they simply flipping the config setting to true by default? Are they replacing the existing "Containers" feature with a new feature which is also called "Containers"? Are they rebranding the Multi-Account Containers extension as "Containers" and making it built-in (seemingly not, since apparently "Not all of the features of the add-on are available in the first-party version of containers").

by ptx

7/21/2026 at 6:22:30 PM

This is great, and the direction Firefox should focus on: creating user-first features that other browsers won't and extension authors can't.

I only wish it was more automated. Every site should automatically get its own container.

How much of the anti-tracking value is defeated by non-cookie browser fingerprinting?

by xnx

7/21/2026 at 6:37:12 PM

I isolate containers by the type of account I am using on there.

So FB gets a different container. Google accounts get a container each. When I need to log in with Google - use the Google account's container.

Work gets different ones - depending on nature of work.

That makes it easy to manage containers for me.

In theory that account's data tracking to an extent is limited. But with browser fingerprinting I doubt this whole set up is very useful once you start aggregating data from multiple providers.

by wtfHN26

7/21/2026 at 6:41:09 PM

Use the Temporary Containers extension, it does just that.

by ashkulz

7/21/2026 at 6:00:15 PM

Oddly enough I thought Firefox had that a few years ago. I forget what I used - maybe a Mozilla extension? - but it even colour-coded tabs.

Am I wrong? Was it unofficial? A hack?

by vintagedave

7/21/2026 at 6:03:16 PM

> For almost a decade, many of you have relied on our Multi-Account Containers extension to keep work, personal, and privacy-sensitive browsing separate without needing multiple browsers or profiles.

> We’ve heard your feedback and understood the value you find in that separation. Now, we’re bringing the power of the Multi-Account Containers extension directly into the heart of Firefox for all to benefit from.

by notatoad

7/21/2026 at 6:03:36 PM

It was an official extension, distributed separately from Firefox, but it was so ubiquitous and a dependency for so many other Firefox extensions, that it would be unusual to not have it installed.

by NoGravitas

7/21/2026 at 6:04:31 PM

The article mentions this extension; it seems like what you're describing: https://addons.mozilla.org/en-US/firefox/addon/multi-account...

by zache6

7/21/2026 at 6:07:00 PM

I have containers on Firefox, and I do NOT have this extension installed.

by ars

7/21/2026 at 6:45:20 PM

They've been available natively on Nightly with some basic UI support since they were first implemented a decade ago. Some other pre-release builds have them too but it's been too long and I cannot remember which ones did or didn't.

by dblohm7

7/21/2026 at 8:34:43 PM

I don't use Nightly and I've been using containers for I think that long without any extension for it.

Edit: looks like I enabled them manually and couldn't remember/find it, it's in about:config under the name "privacy.userContext" instead of "containers".

by Izkata

7/21/2026 at 7:59:25 PM

The Facebok Container extension also makes containers available.

by MaKey

7/21/2026 at 6:03:43 PM

Firefox multicontainers I think it is

by Alifatisk

7/21/2026 at 6:30:43 PM

Multi-Account Containers paired with Container Proxy allows for some really cool setups. I especially like the options to use socks proxies. Hope they will add proper proxy support later.

by svl7

7/21/2026 at 6:33:17 PM

What are the cool setups with proxies?

by warpech

7/21/2026 at 7:13:52 PM

It allows me to access different networks (that might only be reachable via jumphosts or similar) from the same browser. Also at work - some required browser based tools are only accessible via specific proxies. With container specific proxies that's a breeze.

by svl7

7/21/2026 at 6:28:59 PM

My guess as to what's new here is... nothing.

I'm thinking they will change the containers preference to default to on, and if the extension enabled the preference before maybe that's being removed. Otherwise the containers functionality in Firefox or the extensions in the extensions remain exactly as they were before.

So you still need the extension as it has the critical functionality of Ctrl-Shift-1 to open a new tab of the first container type.

by XJ0OYtjb

7/21/2026 at 8:23:03 PM

I am a big user of the multi-account containers extension. It is nice to keep banking in one container, Amazon in its own container, social media in its own, and so on.

Syncing across device and always reopening a certain site/domain inside a specific container are must-have features, so I think I'll keep using the extension until they are available natively.

by sylens

7/21/2026 at 8:22:17 PM

I'm glad that Firefox is catching up, but they still have a lot of catching up to do compared to Arc/Zen. You got people out there like xe-darc innovating on putting Docker containers in your browser, and Firefox is just getting preview support for built in profiles.

by theknarf

7/21/2026 at 8:33:21 PM

What on earth is the use case for a docker container in a browser?

by egamirorrim

7/21/2026 at 6:20:35 PM

But Firefox also has browser profiles now (something I wanted for so long I moved back to chrome to get it), so what’s the purpose of first-party containers now? Don’t browser profiles provide a more robust, very visible delineation between different accounts/user profiles?

by wsgeorge

7/21/2026 at 6:39:19 PM

Firefox has had profiles for a long time (via about:profiles and a command-line argument). Unfortunately, the new profiles are not compatible with the old ones and cannot be migrated.

by rhdunn

7/21/2026 at 6:27:24 PM

A profile is a full new browser, these containers are just tabs. So they mix into the current browser window.

They are much more lightweight, and the workflow is better, just switch tabs.

by ars

7/21/2026 at 7:05:12 PM

I hope they improve the UI, it has been difficult to use. Several menus with different random functionality that don’t have the options I’m looking for. Many times I have to hunt through the extension preferences to do simple things.

Also the “temporary container” extension is quite useful and closer to what I need in the first place.

by mixmastamyk

7/21/2026 at 8:03:19 PM

Does Chrome have this yet? It's basically the single feature I use Firefox for. And no, container tabs & incognito mode don't count.

by coreylane

7/21/2026 at 6:57:36 PM

Amazing news. Wonder if this will be synced on multiple machines through Mozilla Connect, since that wasn't the case with the Mozilla’s Multi-Account Containers extension before.

I hope it is, since it was a major pain point before.

by robinhood

7/21/2026 at 6:59:59 PM

The Multi-account containers extension does sync via Firefox sync, but you have to go into the extension's settings in each browser and manually enable it. Annoying, and took me a while to find it, but it's there at least. Hopefully won't be necessary to manually switch on once containers are a part of Firefox proper.

by sfRattan

7/21/2026 at 7:16:25 PM

Are they shipping it on Android, too?

by fph

7/21/2026 at 6:24:51 PM

tree style tabs and container-locked windows. that will make firefox perfect.

by midnight_eclair

7/21/2026 at 6:06:17 PM

I'm a little confused here, I've been using the containers feature already for years now on Firefox. And I have no add-on installed for it, it just works.

So what is it that they're adding?

by ars

7/21/2026 at 6:10:40 PM

Kubernetes

Serious answer:

> For almost a decade, many of you have relied on our Multi-Account Containers extension to keep work, personal, and privacy-sensitive browsing separate without needing multiple browsers or profiles.

I'm confused too, maybe it's preinstalled, but disabled?

I remember seeing this Fb container symbol in a tab from time to time in my private machine, but I think I did enable something in advance.

Or it's that I just see it extremely rarely due to uBlock origin.

by moritzwarhier

7/21/2026 at 6:56:07 PM

You could have containers but the software itself had no way to manage them. The extension provided the de facto default way to manage them. I think now they are baking the functionality in. I wish they would actually flesh out split tabs. It is so barebones it pissed me off enough to sort of stop using Firefox on a few boxes altogether after decades of use.The browser seems to be the last thing on this company's mind.

by dizhn

7/21/2026 at 8:47:52 PM

No, it's at about:preferences#containers and has been for years if you turn it on in about:config (privacy.userContext.enabled and privacy.userContext.ui.enabled).

by Izkata

7/21/2026 at 8:06:16 PM

I'm curious about Mozilla's seeming shift in strategy (possibly it was awhile ago and I overlooked it):

For a long time, with relatively limited (compared to Google and Apple) development resources, they focused on minimizing upkeep and technical debt. They added and maintained features appealing to the vast majority, the non-technical users, and left the rest to extensions.

Now I'm seeing geek and power user favorites like a built-in color picker, PDF editing features, and now multi-account containers moved into the browser. What changed? Are they focusing on different audience? Do they have new resources so that they can afford maintaining all these additional, more niche features?

by mmooss

7/21/2026 at 7:39:54 PM

I would love to see a better UI for

  - Forcing container usage/default window popup for assigning sites to containers
  - Viewing a list of websites assigned per container

That said I think containers are a great idea, I currently use it to isolate Meta and Amazon sites. Could probably be doing more.

by unethical_ban

7/21/2026 at 8:00:22 PM

[dead]

by glub103011