Security News > 2021 > May > Mozilla starts rolling out Site Isolation to all Firefox channels
Mozilla has started rolling out the Site Isolation security feature to all Firefox channels, protecting users from attacks launched via malicious websites.
Until today, Site Isolation could only be enabled by users of Firefox Nightly, the release channel used by Mozilla to test new features not yet ready for a wider rollout.
Site Isolation has been under development since April 2018 under the Project Fission codename, with Mozilla first announcing plans to add it to the Firefox web browser in February 2019.
The new Site Isolation security architecture acts as an additional security boundary between sites, and it works by completely separating users' web content, loading all sites in separate processes.
You can start testing Site Isolation right now by enabling it on any Firefox release channel, including Release, Beta, or Nightly.
Toggling on Site Isolation is highly recommended given that it "Sandboxes web pages and web frames, isolating them from each other, further strengthening Firefox security."