Mozilla launches Focus by Firefox ad blocker for Safari on iOS 9

Mozilla, the company behind the Firefox web browser, has announced it will launch an ad blocker made for Apple's Safari browser for iOS 9 users. The app, Focus by Firefox, is designed to block web content trackers that are on Disconnect's open source blocklist.

So why is Mozilla getting into the ad blocking business? Denelle Dixon-Thayer, the company's Chief Legal and Business Officer, gives Mozilla's reasons in a blog post:

We made Focus by Firefox because we believe content blockers need to be transparent with publishers and other content providers about how lists are created and maintained, rather than placing certain content in a permanent penalty box. We want this product to encourage a discussion about users and content providers, instead of monetizing users' mistrust and pulling value out of the Web ecosystem. Focus by Firefox is free to users and we don't monetize it in other ways.

Mozilla recently launched the iOS version of Firefox, but the new Focus ad blocker doesn't work with the company's own web browser. However, Mozilla claims that this move was out of their hands:

This was not our choice—Apple has chosen to make content blocking unavailable to third party browsers on iOS. We are exploring how we can provide this feature on Firefox for iOS and will deliver it as soon as it's possible.

Update: The app is now available in the iOS App Store

Source: Mozilla (opens in new tab)

John Callaham

I have been writing professionally about technology and gaming news for 14 years.

  • "We are exploring how we can provide this feature on Firefox for iOS and will deliver it as soon as it's possible." Atomic Web Browser has had built-in ad-blocking for years. Theres no reason Mozilla couldn't have done the same thing on launch date of their app. If it's built into the app, you don't need an external content blocker.
  • Yup. I don't quite get that as well. Maybe there's some performance or memory penalty if they have ad-blocking embedded within their app itself, or maybe they just wanted to depend on the content blockers already available so that they wouldn't have to do the work themselves? Strange, no doubt.
  • The ad-blocker in the browser is different than a content blocker, in Apples world. It's not that cut and dry.
  • The point being, that if Mozilla can't get ad-block to work in their own app via "Content blockers" because Apple doesn't allow it, they still have the option if they choose to just build it directly into the browser.
  • This is why Apple sucks! They are limiting everything! I think soon will have to switch to Android. Mozilla works great for me on iOS, ad-blocker would make it perfect.
  • Mmm, I once (few years ago) decided to jump ship to Android as it seemed more open...
    Yes, it IS more open, open to a lot more garbage that is. Apple is an eco-system, they choose to do so for a reason.
    You only realise how great Apple is, once you jump ship and see how much garbage you get in return.
    Than you will appreciate Apple a whole lot more! ;)
  • I jumped and came back with iPhone 6. I like iOS but it's really too limited. All I want is a little freedom.
  • Freedom to do what? What is IOS holding you back from that caused you to come back to it? The "freedom" of Android must not have tasted all that sweet if it couldn't keep you from coming back.
  • Some ads are not blocked with this app. Ad's by The Deck for example are not blocked at all.
  • There are plenty of domains they do not block:
  • Not to mention that it seems to leave blank white spots to a website where ad should have been. Still using crystal.. Sent from the iMore App
  • Firefox Focus on iOS 10 has a serious problem with pay sites such as It interferes with the login process.