Firefox on Android finally brings desktop-grade protection against malicious tabs

Some Firefox users who installed the latest version 155 update on their devices are spotting a new experimental feature in the browser. It’s called “Website Isolation” and is available in the Firefox Labs section.

As pointed out by users, the feature is disabled by default, so it’s easy to miss if you don’t check the Labs section.

For context, the desktop version of Firefox has had the same protection since 2021 under the name “Fission”. This basically prevents malicious websites from accessing your cookies or login information from another tab. In an earlier announcement, a Mozilla employee explained it as “The main idea of Fission is sandboxing of web content – each web site would be isolated in its own OS process for security.”

The company even updated Firefox 147 with the new architecture earlier this year. And this has been available to users on the Nightly and Beta channels for a while. Plus, users on the Nightly channel won’t see the toggle in the Labs section because it already works without any steps from the user.

What’s new is that the toggle is now on the Release channel with full website isolation.

That said, since it’s still an experimental feature, it does come with some potential downsides. The Labs screen warns that turning it on “may affect performance, stability, website compatibility and how browsing history is saved.”

In our brief testing, we didn’t run into any issues while browsing with the Website Isolation feature enabled. Pages loaded just fine, and we even managed to play a few YouTube videos without any hiccups. Still, that doesn’t guarantee that you won’t face any bugs at all.

Nevertheless, it’s good to see that the feature is finally here for users on the Release channel to try out for themselves.

And speaking of performance, Mozilla has also been working on improving Firefox’s speed, with the latest Firefox 156 beta bringing some performance gains and under-the-hood improvements.

If you want to try it, open Settings, tap Firefox Labs, and look for Website Isolation. You’ll have to restart the browser after turning it on. If the toggle is not there yet, the rollout is still landing in pieces. Leave it off if you care more about smooth playback than an extra security layer right now.

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