uBlock Origin - An efficient blocker for Chromium and Firefox. Fast and lean.
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Couple of ongoing myths to dispel:

I've seen in many places lately the following assertion (example):

ublock blocks ads just like adblock plus, but triggers the ads API to think it got viewed

Completely false. uBlock Origin (and uBlock) does not "trigger" any "ads API" (whatever that is). It prevents network requests from being made according to filter lists so that your browser does not connect to remote servers, period.

Also, as opposed to what uBlock FAQ suggests:

[...] In contrast, the uBlock project will be moving forward with awesome new features, refinements, and enhancements [...]

uBlock Origin is also actively maintained and is also moving forward with new features, refinements, and enhancements and stability work. For a neutral assessment of the differences between uBlock Origin and uBlock, it is best to rely on Wikipedia's article on uBlock.

uBlock Origin

pronounced you-block origin (/ˈjuːˌblɒk/) — you decide what enters your browser.
English, Chinese (中文), Korean (한국어)

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


uBlock Origin (or uBlock₀) is not an ad blocker; it's a general-purpose blocker. uBlock₀ blocks ads through its support of the Adblock Plus filter syntax. uBlock₀ extends the syntax and is designed to work with custom rules and filters.

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. uBlock₀'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 µMatrix).

EasyList, Peter Lowe's Adservers, EasyPrivacy and Malware domains are enabled by default when you install uBlock₀. Many more lists are readily available to block trackers, analytics, and more. Hosts files are also supported.

Once you install uBlock₀, you may easily un-select any of the pre-selected filter lists if you think uBlock₀ blocks too much. For reference, Adblock Plus installs with only EasyList enabled by default.


Quick guide: popup user interface

For advanced usage, read about dynamic filtering and more on uBlock₀'s wiki.



On average, uBlock₀ really does make your browser run leaner. [1]

Chromium [2]


[1] Details of the benchmark available at Firefox version: benchmarking memory footprint.

[2] Important note: There is currently a bug in Chromium 39+ which causes a new memory leak each time the popup UI of an extension is opened. This affects all extensions. Keep this in mind when measuring Chromium's memory usage. In the benchmarks, I avoided opening the popups completely.


uBlock₀ is also easy on the CPU

Details of the benchmark available in this LibreOffice spreadsheet.


Being lean and efficient doesn't mean blocking less

For details of benchmark, see uBlock₀ and others: Blocking ads, trackers, malwares.

Quick tests


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


You can install the latest version manually, from the Chrome Store, or from the Opera store.

Alternatively, you can install chrisaljoudi/uBlock from Chrome store. Slightly different feature set, same performance.


Firefox Add-ons web site, or install manually by downloading the latest uBlock0.firefox.xpi file, and by dragging the downloaded xpi file to your add-on page.

Alternatively, you can install chrisaljoudi/uBlock from Firefox Add-ons homepage. Slightly different feature set, same performance, proper support for legacy Firefox-based browsers.


There is no support for Safari for uBlock Origin.

Best is that you install chrisaljoudi/uBlock, which has official support for Safari.

Note for all browsers

To benefit from uBlock Origin's higher efficiency, it's advised that you don't use other inefficient blockers at the same time (such as AdBlock or Adblock Plus). uBlock₀ will do as well or better than most popular ad blockers.

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 uBlock₀ on Crowdin.