For a decade, uBlock Origin was the answer. Free, open source, light on memory, unmatched at blocking — if you were technical, it was the only ad blocker worth installing. Then the platform moved.
Google's Manifest V3 removed the webRequest API that uBlock Origin relied on and replaced it with the more limited declarativeNetRequest. The full version left the Chrome Web Store in late 2024, and Chrome permanently disabled the remaining Manifest V2 extensions in July 2025 — and millions of people who never thought about their ad blocker went looking for a uBlock Origin alternative that still worked on Chrome.
If your blocker no longer runs — and even when it did, it never told you what the ads it missed actually cost — what were you really measuring?
This article covers the real uBlock Origin alternatives in 2026 — what each one blocks, where it runs, and the dimension every one still leaves invisible: the carbon footprint of the ads that load anyway.
What happened to uBlock Origin on Chrome
uBlock Origin (the full version, by Raymond Hill / gorhill) used Chrome's webRequest API to inspect and cancel network requests dynamically — the foundation for its per-site filtering depth. Manifest V3 deprecated that in favour of declarativeNetRequest, which works from predefined rule lists rather than live interception.
- Late 2024 — full uBlock Origin removed from the Chrome Web Store.
- July 2025 — Chrome disabled the remaining Manifest V2 extensions; installed copies stopped working.
- Now — uBlock Origin Lite (uBOL), also by gorhill, is the official MV3-compliant replacement on the Chrome Web Store.
Two things drive the search. Most people want the closest blocker that still runs on their browser. And increasingly the search is professional: agencies and advertisers now have to account for ad emissions under incoming EU rules, and blockers reduce what they see without ever quantifying what they consumed. Either way, not one of these tools reports the carbon footprint of the ads it blocks, lets through, or that fire before blocking engages.
The closest alternatives
uBlock Origin Lite is the natural first stop on Chrome — same author, MV3-compliant, fully open source, very light. It blocks well in its default mode but doesn't match the full version's dynamic, per-site filtering.
Ghostery runs across all major browsers plus its own mobile browser; its strength is tracker categorisation, privacy-first rather than maximum-depth. AdGuard is a free extension plus a paid desktop app (around $2.49/month) that filters system-wide traffic. Brave isn't an extension at all — it's a Chromium browser with blocking built in at the engine level, so it isn't bound by the same MV3 limits.
| Alternative | Type | Runs on | Open source | MV3 limited? |
|---|---|---|---|---|
| uBlock Origin Lite | Extension | Chrome, Edge | Yes | Yes |
| uBlock Origin (full) | Extension | Firefox | Yes | No |
| Ghostery | Extension | All major browsers + mobile | Mostly | On Chrome, yes |
| AdGuard extension | Extension | All major browsers | Filter engine yes | On Chrome, yes |
| AdGuard desktop | App ($2.49/mo) | macOS, Windows, Android, iOS | No | No |
| Brave Shields | Browser | Brave (desktop + mobile) | Yes | No |
For the wider blocker comparison — Ghostery, Pi-hole, the mobile picture — see our companion piece on AdGuard alternatives. None of those rows carry a column for ad carbon, because none of them measure it.
Firefox: the full version
The cleanest answer to 'I want the real uBlock Origin back' is to run it on Firefox. Mozilla kept the webRequest API, so the full version — dynamic filtering, per-site rules, the complete experience — still works there with no degradation. For many former Chrome users, the 2026 setup is simply Firefox plus full uBlock Origin.
It is also still only a blocker. Firefox plus full uBlock Origin blocks more than anything on Chrome — and measures exactly as much as everything on Chrome: nothing.
What blockers don't measure
Switch to uBO Lite, move to Firefox, or add Brave — and you've optimised one thing: how many ads you see. None of these tools tell you:
- How many invisible impressions fired before the blocker engaged. (We unpack this in viewability vs. attention.)
- Which ads loaded into viewable iframes that billed an impression whether or not you scrolled to them.
- The carbon footprint per impression — the Ebiquity / Scope3 average is around 670g CO₂ per 1,000 display impressions, higher for video.
- That even a blocked impression often still travels the supply chain before your browser ever cancels it.
That gap is the point of this comparison. Manifest V3 reshaped what a blocker is allowed to do; it left the measurement question untouched. No version of uBlock Origin — on any browser — tells you the carbon of the ads that load. Lumotraq does: it runs alongside whichever blocker you land on and measures the per-impression ad carbon the blocker can't see — the one layer Manifest V3 has no say over. How it measures is documented at lumotraq.com/methodology; the reporting and disclosure side sits in frameworks and standards.
Choosing your alternative in 2026
- Closest free swap on Chrome? uBlock Origin Lite.
- The real full uBlock Origin? Firefox.
- Blocking built into the browser? Brave.
- Privacy-first with a cleaner dashboard? Ghostery.
- System-wide on desktop or mobile? AdGuard.
- Want to know what your remaining ads cost in carbon? Lumotraq, alongside any of the above.
Manifest V3 closed one chapter — the era of one extension that did everything on Chrome. It opened a more honest question: now that you've chosen how to block, do you know what still gets through, and what it emits? Blocking is a 2010s solution that still works. Measurement is what 2026 adds.