Ka-Block! is a content blocker for Safari that prevents ads and tracking scripts from slowing down web pages you visit.

Many sites use third-party scripts to track your behavior across the web, causing pages to load slowly and draining your Mac’s battery. Blocking these scripts dramatically improves page load time, data usage, and battery life.

- Fast, curated filter list
- Open source
- Also available for Safari on iPhone

Protecting privacy and performance on the web is important. We hope you enjoy Ka-Block!

What's New

Version 3.1

Updates to the filter list.

Customer Reviews

4.9 out of 5

10 Ratings

10 Ratings

Simple and Elegant


Compared to other ad blockers this really is the simplest and most elegant solution. It uses virtually no extra resources and blocks everything I need. Not sure if I understand any advantage of downloading from the Mac App Store as compared to Safari’s extension gallery. it’s a 4 MB download here but only 160 Kb from the extensions gallery and I don’t end up with another program cluttering up my applications folder.

Effective !!


Thank you David and Josh for the excellent extension. (Yes, I visited your website). It works without a glitch.

Beware: only installs in Safari


Safari Technology Preview is set as my default browser, but when I tried to add Ka-Block to STP 50, it loaded in Safari instead. I previously reported a bug stating that STP takes me to the new Safari Extensions on the Mac App Store, someone at Apple wrote back that is the expected functionality. I couldn’t wait to try it! When I clicked “Get," Safari was closed. Since I didn’t see it in STP, I checked Safari and there it was. Now, there doesn’t seem to be a way to install Ka-Block into STP. The basic Safari Extensions web page now directs me to the Mac App Store. I wish the Mac App Store stated "Safari only" on each extension.


Negative Code, LLC
4 MB
Age Rating
Rated 4+
© 2015-2018 David Graham & Josh Peek


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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