Firefox Containers are no longer an add-on you have to go and find. With Firefox 153, released on 21 July 2026, Mozilla has built the feature directly into the browser, so every Firefox user now has a way to keep work, banking, shopping and personal browsing in separate, sealed compartments inside one window. It is the biggest user-facing change in this release — and it arrives as a preview, with some of the old extension’s abilities still missing.
What Firefox Containers actually do
The idea is separation of identity. Mozilla’s own description in the Firefox 153 release notes puts it plainly: Containers “let you keep separate parts of your online life (work, shopping, personal, banking) logged into different accounts in the same browser window, but keep your cookies and ad tracking isolated inside each container.”
In practice that means two things. First, you can be signed into two accounts on the same site at once — a personal Gmail in one container and a work one in another — without juggling profiles or private windows. Second, and more importantly for privacy, the cookies a shopping site drops on you stay inside the shopping container. As Mozilla puts it on its blog, “stuff you do in one container isn’t seen by other containers.” An ad network that fingerprints you while you browse a retailer does not get to carry that profile across into your banking tab.
This is not the same thing as a VPN or private browsing. Containers do not hide your IP address, and they do not stop a site knowing who you are once you log in. What they stop is the quiet joining-up of your activity across sites that would otherwise all share one cookie jar.
How to try it
Containers are on by default in Firefox 153 — there is nothing to install. Mozilla describes three ways in: right-click any tab to open it in a container, long-press the new tab (+) button, or go into Firefox Settings to create your first container, where you can give it your own name, colour and icon. In hands-on coverage, OMG! Ubuntu reports that Firefox ships four ready-made containers — Personal, Banking, Shopping and Work — and that container tabs are colour-coded with a matching icon in the address bar so you can see at a glance which compartment you are in.
What is still missing
This is where Mozilla is being unusually honest, and readers should take it at face value. In its announcement, the company writes:
Not all of the features of the add-on are available in the first-party version of containers just yet, we’re still building them out.
So if you already run the Multi-Account Containers extension, do not uninstall it. Mozilla says existing users need take no action and the add-on will keep working alongside the built-in version. Mozilla has not published a line-by-line list of what is missing, so the safe assumption is that anything you rely on the add-on for today may not yet have an equivalent built in.
It is worth saying that this took a long time. Multi-Account Containers has been available as an optional add-on for years, which meant a genuinely useful anti-tracking tool only ever reached the small slice of users who went looking for it. Building it into the browser is the right call. Shipping it incomplete is the trade-off, and it leaves the people who care most about it — the existing extension users — as the ones who still cannot fully switch.
The rest of Firefox 153, in brief
- Extensions can no longer access local files by default — a meaningful tightening, given how much reach browser add-ons have historically had.
- Local Network Access restrictions on by default — stops web pages quietly probing devices on your home network.
- Location permission icon now turns red when a site is actively reading your location.
- HDR video playback on Windows, for displays with HDR enabled in Display Settings.
- QR code generation for sharing the page you are on to your phone.
- PDF improvements — merge PDFs by dragging them into the sidebar, and insert images as new pages.
- Experimental JPEG XL support, and quicker access to Firefox Labs by typing
labsin the address bar.
Should you update?
Yes — the two default-on restrictions above are worth the update on their own, regardless of whether Containers appeals to you. Firefox updates itself in the background, but you can force it from the hamburger menu under Help, then About Firefox, which checks and applies the update immediately. On Linux, wait for your distribution’s package or use the Flatpak or Snap build, depending on how you installed it.
Sources: Firefox 153 release notes, The Mozilla Blog, OMG! Ubuntu
