uBlock Origin: fast, lean ad and tracker blocker
/uBlock
uBlock Origin blocks ads, trackers, and malware sites the moment you install it, with no configuration required. The catch: Chrome is removing all Manifest V2 extensions, uBlock Origin included, from the Web Store on August 31, 2026, so Chrome users are on borrowed time. Firefox is where uBlock Origin keeps its full filter engine intact, with no such deadline. Install it on Firefox if you want it to keep working past 2026.
What is uBlock Origin?
uBlock Origin is a free, open-source browser extension that blocks ads, trackers, coin miners, popups, anti-adblock scripts, and malware sites in Chromium and Firefox. It ships with EasyList, EasyPrivacy, Peter Lowe's Blocklist, and the Online Malicious URL Blocklist on by default, plus its own uBO lists. It reads standard EasyList filter syntax, extended with its own custom-rule syntax, and also supports hosts files.
What uBlock Origin blocks by default
- ✓Ads, trackers, coin miners, popups, and malware sites blocked out of the box, no setup needed.
- ✓Filter lists on by default: EasyList, EasyPrivacy, Peter Lowe's Blocklist, the Online Malicious URL Blocklist, and uBO's own lists.
- ✓Extended filter syntax that goes beyond plain EasyList, for writing your own custom blocking and unblocking rules.
- ✓Hosts file support, for anyone who prefers blocking at that level instead of filter lists.
- ✓Anti-adblock-defusing logic, so sites that try to detect and shut out ad blockers get worked around.
- ✓Advanced Mode adds a point-and-click firewall you can configure per site.
- ✓You can deselect any preselected list if uBlock Origin is blocking more than you want.
Installing uBlock Origin on your browser
Install uBlock Origin from Firefox Add-ons for the version the README says works best, with full desktop and Android support. On Chromium browsers, install from the Chrome Web Store, Microsoft Edge Add-ons, or Opera Add-ons; uBlock Origin should be compatible with any Chromium-based browser. Chrome's Web Store listing carries a removal notice for August 31, 2026, tied to Google's Manifest V2 phase-out. For newer builds than the store allows, or for Thunderbird (whose add-on listing is stuck at 1.49.2), the README points to GitHub Releases and manual installation — those builds won't auto-update. There's also a documented path for enterprise deployment linked from the README.
Strengths
- ✓Broad default coverage — ads, trackers, coin miners, popups, anti-adblock scripts, and malware domains are all blocked out of the box.
- ✓Built for efficiency: the project's stated design goal is low CPU and memory use, not just more filters.
- ✓Filter lists are transparent and swappable — you can turn off any preselected list if uBlock Origin blocks more than you want.
- ✓Extended filter syntax beyond stock EasyList lets you write your own custom rules instead of waiting on a list maintainer.
- ✓Advanced Mode's per-site firewall gives point-and-click control when the defaults aren't enough.
- ✓Actively translated project — a Crowdin page exists for localizing the interface.
Chrome's Manifest V3 deadline and the uBO future
- △Chrome is removing all Manifest V2 extensions, uBlock Origin included, from the Web Store on August 31, 2026 — after that, Chrome users can only sideload it manually.
- △Microsoft Edge is following Chrome's lead: its consumer MV2-to-MV3 transition starts in August 2026, aims to finish by the end of 2026, with enterprise deprecation in early 2027.
- △The Thunderbird Add-ons build is no longer updated and stuck at version 1.49.2; anyone wanting a current version has to install manually from GitHub Releases.
- △Manual GitHub Releases builds for Chromium MV2 and Thunderbird don't auto-update, so you're on the hook for checking for new versions yourself.
- △The README warns against running uBlock Origin alongside any other content blocker, since another blocker can break its privacy and anti-blocker-defusing features.
Alternatives to uBlock Origin
Frequently asked questions about uBlock Origin
uBlock Origin's current Manifest V2 version won't be installable from the Chrome Web Store after August 31, 2026, when Google removes all remaining Manifest V2 extensions. Chrome users will need to sideload it manually from GitHub Releases or switch to a Manifest-V3-based build to keep using it.
uBlock Origin is free and open-source software, licensed under the GPLv3. The README frames it as built by users for users, with no donation asks anywhere.
uBlock Origin is designed to be light on CPU and memory, which is where the name comes from. The README cites third-party testing showing it performs as well as or better than blockers, and advises against running it next to another content blocker since that can interfere with its filtering and anti-adblock defusing.
uBlock Origin ships with EasyList, EasyPrivacy, Peter Lowe's Blocklist, the Online Malicious URL Blocklist, and its own uBO filter lists enabled by default. AdBlock Plus, by contrast, installs with only EasyList, ABP filters, and Acceptable Ads turned on — the README says so directly, meaning uBlock Origin blocks considerably more out of the box.
uBlock Origin has official listings on Firefox Add-ons, Microsoft Edge Add-ons, and Opera Add-ons, and the README says it should be compatible with any Chromium-based browser. Firefox is where the project says uBlock Origin works best, with support for both desktop and Android.
uBlock Origin blocks trackers by design, not as an afterthought — EasyPrivacy is one of the filter lists enabled by default specifically for that. It also blocks coin miners, popups, and known malware-serving domains via the Online Malicious URL Blocklist, alongside the ad-blocking rules from EasyList.
The problem it solves
Browsers ship with no blocking at all, and the people who do install something usually land on one of two extremes: an extension that blocks too little because the vendor baked in an "acceptable ads" allowlist, or one so aggressive it breaks half the sites they visit. uBlock Origin's problem to solve is narrower: give people a blocker whose defaults are curated (EasyList, EasyPrivacy, and a few others) but that doesn't turn the browser sluggish, and whose rules can be inspected and changed instead of trusted blindly.
Best use cases
- •Browsing Chromium or Firefox with ads, trackers, and popups blocked by default, no filter-list shopping required.
- •Blocking known malware and phishing domains at the browser level via the Online Malicious URL Blocklist.
- •Locking down a specific site's third-party requests with Advanced Mode's per-site firewall.
- •Replacing hosts-file-based blocking with a filter-list approach that's easier to update.
- •Deploying to Thunderbird via the (no-longer-updated) Thunderbird Add-ons build for feed blocking, not email.
Who should try it — and who should skip
Anyone who wants ad, tracker, and malware-site blocking without curating filter lists themselves should install uBlock Origin and leave the defaults alone — that's exactly the install-it-and-forget-it case Basic Mode is built for. People who want to fine-tune blocking per site, or who don't want to trust one vendor's default list choices, get more out of Advanced Mode's firewall. Skip it, at least on Chrome, if you need guaranteed long-term support without a manual reinstall — Firefox doesn't have that clock running, so it's the safer install today. Thunderbird users should also know the official add-on is frozen at 1.49.2 and should go straight to GitHub Releases for anything newer.
Related repositories
Is uBlock worth your time?
ChatGPT, Claude and Perplexity can all read this page. Ask one of them what it makes of uBlock.