To create a working instance of uBlock Origin's static network filtering engine

uBlock, uBO, adblock, trie, blocker, browser-extension, chromium, firefox, javascript, ublock-origin
npm install @gorhill/ubo-core@0.1.25


Commit rate Issues Crowdin License NPM Mozilla Add-ons Chrome Web Store

uBlock Origin

pronounced you-block origin (/ˈjuːˌblɒk/) — you decide what enters your browser.
BEWARE! uBlock Origin is (and has always been) COMPLETELY UNRELATED to the web site ublock.org.

Get uBlock Origin for Firefox Get uBlock Origin for Chromium Get uBlock Origin for Microsoft Edge Get uBlock Origin for Opera
Do not use uBlock Origin along with other similarly-purposed blockers.
See below for more installation options.

An efficient blocker add-on for various browsers. Fast, potent, and lean.

uBlock Origin is NOT an "ad blocker": it is a wide-spectrum blocker -- which happens to be able to function as a mere "ad blocker". The default behavior of uBlock Origin when newly installed is to block ads, trackers and malware sites -- through EasyList, EasyPrivacy, Peter Lowe’s ad/tracking/malware servers, Online Malicious URL Blocklist, and uBlock Origin's own filter lists.


Basic mode Advanced-user mode
Popup user interface A point-and-click firewall which can be configured on a per-site basis


Configure as you wish:
picture shows 3rd-party scripts and frames blocked by default everywhere

Visit the uBlock Origin's wiki for documentation.

For support/questions/help, there is /r/uBlockOrigin on Reddit.


uBlock Origin (or uBlock₀) is not an ad blocker; it's a general-purpose blocker. uBlock Origin blocks ads through its support of the Adblock Plus filter syntax. uBlock Origin extends the syntax and is designed to work with custom rules and filters. Furthermore, advanced mode allows uBlock Origin to work in default-deny mode, which mode will cause all 3rd-party network requests to be blocked by default, unless allowed by the user.

That said, it's important to note that using a blocker is NOT theft. Don't fall for this creepy idea. The ultimate logical consequence of blocking = theft is the criminalisation of the inalienable right to privacy.

Ads, "unintrusive" or not, are just the visible portions of privacy-invading apparatus entering your browser when you visit most sites nowadays. uBlock Origin's main goal is to help users neutralize such privacy-invading apparatus — in a way that welcomes those users who don't wish to use more technical, involved means (such as uMatrix).

EasyList, EasyPrivacy, Peter Lowe's, Online Malicious URL Blocklist and uBO's own lists are enabled by default when you install uBlock Origin. Many more lists are readily available to block trackers, analytics, and more. Hosts files are also supported.

Once you install uBlock Origin, you may easily un-select any of the pre-selected filter lists if you think uBlock Origin blocks too much. For reference, Adblock Plus installs with only EasyList, ABP filters and Acceptable Ads enabled by default.


Feel free to read about the extension's required permissions.


You can install the latest version manually, from the Chrome Web Store, or from the Opera add-ons.

There is also a development version in the Chrome Web Store if you want to test uBlock Origin with the latest changes: see uBlock Origin dev build.

It is expected that uBlock Origin is compatible with any Chromium-based browsers.

Firefox / Firefox for Android

Firefox Add-ons web site.

There is also a development version if you want to test uBlock Origin with the latest changes: for installation, see Install / Firefox webext / For beta version

uBlock Origin is compatible with SeaMonkey, Pale Moon, and possibly other browsers based on Firefox: for installation, see Install / Firefox legacy.

uBO may also be installed as a Debian package:

  • Firefox 56-: apt-get install xul-ext-ublock-origin
  • Firefox 55+: apt-get install webext-ublock-origin

There is no guarantee the package will be available on your specific platform -- in which case, you will have to install from Firefox Add-ons web site.

Microsoft Edge

Publisher: Nicole Rolls.

Chromium-based Edge: Stable version available in Microsoft Edge Add-ons.

Safari (macOS)

Developer: @el1t.

Development version available at https://github.com/el1t/uBlock-Safari#ublock-originfor-safari.

Warning: It is not possible for extensions like uBlock Origin to work with Safari 13+. See el1t#158.

Note that issues specific to the Safari fork are the responsibility of the current maintainer, I have no control over the code base of the fork.

Note for all browsers

To benefit from uBlock Origin's higher efficiency, it's advised that you don't use other content blockers at the same time (such as Adblock Plus, AdBlock). uBlock Origin will do as well or better than most popular ad blockers. Other blockers can also prevent uBlock Origin's privacy or anti-blocker-defusing features from working properly.


Below is documentation to assist administrators in deploying uBlock Origin:

Release History

See the releases pages for a history of releases and highlights for each release.


uBlock Origin's manifesto.

Free. Open source. For users by users. No donations sought.

Without the preset lists of filters, this extension is nothing. So if ever you really do want to contribute something, think about the people working hard to maintain the filter lists you are using, which were made available to use by all for free.

You can contribute by helping translate uBlock Origin on Crowdin.