Firefox Focus on iOS blocks 78% with all tracker blocks are enabled, and 62% with the last “Block other content trackers” option disabled. Percentage figures are from test on https://d3ward.github.io/toolz/adblock.html.
Firefox Focus is a nice browser for certain use cases, but it can't compare to uBlock Origin, which scores 100% on that test for me on a fresh install with default settings (using Firefox on Android and desktop).
It's interesting how Firefox Focus on iOS also acts as a Content Blocker for Safari, but I find AdGuard to be more comprehensive on iOS.
Increasing YouTube ad display rates on mobile drove me to using the (somewhat clunky) AdGuard share button in safari that blocks ads when using YT in Safari. I’m just glad there is some option on iOS.
It is funny that Android has better adblock features (uBO on Firefox).
I was replying specifically to the first paragraph in the parent comment that other apps on iOS are not able to implement content blockers. Firefox Focus does appear to do just that. Obviously, not as effectively as uBlock Origin (thanks for testing!) but uBO isn’t yet available to install on Firefox on iOS.
(Edit since I can’t reply):
Firefox Focus does appear to implement iOS content blocker since it appears as an option under Safari settings for content blockers.
Firefox (standard and Focus) and other iOS browsers can block ads and trackers, but not as comprehensively as that API can. That API is limited to Safari due to platform restrictions, which I hope get removed in the future.
Firefox Focus appears under Safari settings > content blockers, along with more typical blockers like AdGuard. I think they both implement Content Blocker API.
The way Firefox Focus is implemented on iOS is a little complicated, since it's both a browser and a Content Blocker. As of 2017, Firefox Focus uses WKWebView as the webview component: https://github.com/mozilla-mobile/focus-ios/pull/507
WKWebView does not support the Content Blocker API. Ad blocking apps that use the Content Blocker API are only compatible with Safari and the SFSafariViewController component, which is very feature-limited and not suitable for a full web browser app:
As a workaround, Firefox Focus uses script injection to block ads and trackers within the browser part of itself, but the Content Blocker part of Firefox Focus only affects Safari:
However, both Firefox Focus and Safari (with the Firefox Focus Content Blocker enabled) score 78% on that test, so Firefox Focus might be good enough for web browsing on iOS if you're comfortable with its feature set and don't need the additional filter lists or custom rules that another third-party Content Blocker would offer.
Apple should still allow third-party browsers to use third-party Content Blockers, since this restriction is an unnecessary handicap for any non-Safari browser on iOS.
Brave on iOS only scores 77% for me with the default settings, which includes the "Block cross-site trackers" Shield setting. Do you have some other setting enabled?
One rather effective way to get much higher (approx 99%) on iOS is to use a DNS over HTTPS provisioning profile (or app), and use a DNS server that blocks ads.
If you run your own server, you can get to 100% by turning on blocking for a couple of hosts not in standard blocklists that this test has highlighted.
The DNS setting applies to most or all apps, as far as I can see, as it's applied as a system level provisioning setting. iOS 15 gives more visibility of this in the UI, but it works in iOS 14.
