Mozilla has begun rolling out a native ad-blocking feature for Firefox on iOS, moving it out of experimental status after weeks of anticipation. Because Apple requires all iOS browsers to render pages using its own WebKit engine rather than a browser's preferred back end, Mozilla could not offer its usual extension-based ad blockers and instead had to build blocking directly into the browser using Apple's WebKit Content Blockers, which Apple designed for better performance than traditional JavaScript-based ad blockers.

The feature is off by default and being rolled out gradually, with users needing to enable it manually via Browsing settings and switch on "Remote Improvements," which lets Mozilla push updates between releases; this was decoupled from telemetry collection following February's Firefox 148 release. Once active, it blocks ad trackers, third-party adverts and pop-ups, but notably does not remove ads on search results pages or sponsored content on Firefox's own home and new-tab pages, nor ads served directly by websites. Mozilla says it has no plans to extend built-in ad blocking to desktop or Android, where it will continue relying on its existing extension ecosystem.