# Adblock Fast and the case for twelve blocking rules

> Adblock Fast is a GPL-3.0 ad blocker for Windows, Android, iOS and Chrome that ships a dozen filtering rules instead of the tens of thousands used by list based blockers. Its own benchmark numbers were measured in 2015, which is the first thing to weigh.

**rocketshipapps/adblockfast** — Adblock Fast is a faster ad blocker for Windows, Android, iOS, Chrome, and Opera.

- Repository: https://github.com/rocketshipapps/adblockfast
- Website: https://adblockfast.com/
- Stars: 787 · Forks: 193
- Language: Objective-C
- License: GPL-3.0
- Published: 2026-10-20 · Updated: 2026-10-20 · Language: en
- Canonical page: https://hysenlabs.com/projects/rocketshipapps-adblockfast

## Twelve rules instead of sixty-five thousand

The idea behind Adblock Fast is subtraction. The README argues that ad blockers have grown bloated with rarely used filtering rules and features that slow them down, and that the fix is to execute a very small number of rules instead. The project states that it runs 12 optimized filtering rules where AdBlock and Adblock Plus run 65,316.

For Chrome and Opera, the rules live in a single JavaScript file in the repository, referenced by the README as the project's own ruleset at `opera/chrome/scripts/blocking.js`. The comparison figures for the two competing blockers come from EasyList, the shared filter list, which is where the rule count gap comes from. One project ships its own small hand written ruleset, the others consume a community list that grows without limit.

That distinction is the whole design, and it cuts both ways. Fewer rules means less work per page and a smaller install, and it also means the coverage of what actually gets blocked is bounded by a dozen hand maintained entries instead of thousands of community contributed ones.

## The published benchmarks were measured in 2015

The README leads with five numeric comparisons, and they are worth reading with their footnotes rather than as headline figures.

The rule counts were retrieved on December 3rd, 2023, from EasyList and from the Adblock Fast ruleset. The other four sets of numbers, covering file size, page load time, CPU use and memory use, were all measured in Chrome on September 1st, 2015. The method is described in detail: enable each app, clear the browser cache before each trial, load the homepage of each of a list of top news sites three times, record the value shown in the browser's developer tools or task manager when the load event fired, and take the mean.

On those measurements Adblock Fast loaded pages in 2.10 seconds against a 3.17 second control, used 6.6 percent CPU against about 20 percent, and 58.5 MB of memory against roughly 160 MB, with a 97 KB install against 543 KB and 843 KB. The direction of those numbers is consistent with the design. The date is eleven years old, and the README does not present newer measurements, so the sensible reading is that the architecture argument holds while the specific figures are historical.

## A toolbar button reports what was blocked

On Chrome the extension installs a button in the toolbar, and the button is a small status readout with four states. It distinguishes ads being blocked and ads found on the page, ads being blocked with no ads found, ads not blocked while ads are present, and neither blocked nor found. The README shows each state as an image from the project assets.

There is a practical escape hatch. If the extension interferes with the behaviour of a page, clicking the button unblocks ads for that site, and the README says that choice is remembered when you return to the site. That is a per site allow list implemented in the extension itself, which is the one piece of fine grained control that a twelve rule design can offer without carrying a large filter list.

Showing the extension button takes two clicks in Chrome: open the extensions (puzzle) button in the toolbar, then click the pin button next to the extension listing.

## On phones the blocker lives in a system content blocker list

Mobile installation is different in kind, because the ad blocking happens through the platform rather than in the browser. On Android the project supports the Samsung Internet browser 4.0 and up, and the README says plainly that it does not block ads in other apps. To enable it you open the Home button, tap the Internet app, use the toolbar button in the top right corner to reach Extensions and then Content blockers, and toggle the Adblock Fast switch on. To unblock ads, you go to the Adblock Fast app.

On iOS the same shape applies to Safari. Open the Home button, tap Settings, then Safari, then under General find Content Blockers and toggle the Adblock Fast switch on. The README adds a caveat that Safari caches aggressively, so to see the effect on a particular page you may need to clear Safari's cache by going to Settings, then Safari, then Clear History and Website Data before reloading.

The platform support is listed in the README as Windows 7 and up, Android 5.0 and up with Samsung Internet 4.0 and up, and iOS 9 and up on 64 bit devices, iPhone 5s and up and iPad mini 2 and up. No install command is given anywhere in the documentation, because these are app store and browser store installs rather than something you build.

## Opera support has been crossed out

The repository still contains an `opera/` directory and the Chrome and Opera extensions share the same source layout, but the README strikes Opera out of the supported list in both the headline and the browser section. The last entry in the download list is a struck through Opera line.

The repository layout explains why. Alongside `opera/` there are separate top level directories for `windows/`, `android/`, `ios/`, `www/` and `network/`, plus `build.sh` and a `builds/` directory, so this is a multi platform product built from one repository rather than a single browser extension. The Opera extension was built from the same code as the Chrome one and is still in the tree, but the documentation no longer presents it as supported.

If you are on Opera, the evidence in the repository is not enough to conclude that the extension still works. The README is the authoritative source here and it no longer lists Opera.

## Where a twelve rule blocker is the wrong tool

The clearest case against is that ad coverage is the product. A list based blocker exists to apply thousands of patterns contributed by a large community, and it can hide an ad from a site nobody has written a rule for. A hand maintained ruleset of 12 entries cannot. The README's own comparison shows the gap: 12 rules against 65,316, with the competitor's count taken from EasyList.

The second limit is the feature set that comes with those rules. The project does not describe a subscription list service, a community reporting flow for broken sites, cosmetic filtering that hides the empty space left behind, or per site allow and deny lists beyond the single site override on the toolbar button. If any of those matter to you, the README gives no evidence that they exist here.

Third, the evidence base is old. The performance comparisons were taken in 2015 with a specific method on a specific set of news sites, and the README has not published a refreshed run. That does not make the project bad, but it does mean the numbers on the front page are not a measurement of what you will experience today.

## Per platform versions and a GPL-3.0 licence

Releases are cut per platform rather than as one stream. The tags listed for the repository are s2.5.0 from 2025-01-17 and a2.5.0 from 2024-11-02, with a2.4.2 shortly before that, which suggests separate versioning for the browser extension and the Android application rather than a single release train. The default branch is main, and the last push was on 2026-10-13, so the repository is receiving changes even though the most recent tagged release is older.

The licence is GPL-3.0, with the terms in LICENSE.txt at the repository root. The README itself does not discuss licence terms beyond naming the licence, so if the distribution model of a build matters to your use, the file at the root is the place to read rather than this description.

The project is built and maintained by Rocketship, and the homepage given in the repository metadata is adblockfast.com, where the per platform downloads are listed.

## Conclusion

Adblock Fast suits someone who wants a light, low resource blocker and is willing to accept narrow ad coverage, on Windows, Android, iOS or Chrome, and accepts that the project is not an easyList. It does not suit you if you depend on per site filtering, cosmetic filters or a maintained subscription list. Before installing, note that the README's speed and memory figures were measured on September 1st, 2015, and judge the project on the current build rather than on those numbers.

## FAQ

### How does Adblock Fast differ from Adblock Plus?

Adblock Fast executes 12 filtering rules of its own, while Adblock Plus consumes the EasyList, which the README counted at 65,316 rules on December 3rd, 2023. The result is a much smaller install and less work per page, with less coverage of individual ad patterns.

### How do I enable Adblock Fast on iOS?

Open Settings, then Safari, then under General find Content Blockers and toggle the Adblock Fast switch on. The README notes you may need to clear Safari's cache before reloading to see the effect on a page.

### Does Adblock Fast still support Opera?

The README strikes Opera out of its supported browser list, although an opera directory with the extension source still exists in the repository. Chrome and Opera share the extension code, but the documentation no longer lists Opera as supported.

### Can I turn Adblock Fast off for a single site?

Yes. The README says that if the extension interferes with a page, clicking the toolbar button unblocks ads for that site, and that the choice is remembered when you return to the site.

### When were the Adblock Fast benchmark numbers measured?

The benchmark notes state that file size, load time, CPU and memory figures were measured in Chrome on September 1st, 2015, while the rule counts were retrieved on December 3rd, 2023.

## Sources

- [License: GPL-3.0](https://github.com/rocketshipapps/adblockfast/blob/main/LICENSE)
- [Project website](https://adblockfast.com/)
- [README](https://github.com/rocketshipapps/adblockfast/blob/main/README.md)
- [Releases](https://github.com/rocketshipapps/adblockfast/releases)
- [rocketshipapps/adblockfast on GitHub](https://github.com/rocketshipapps/adblockfast)

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Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/rocketshipapps-adblockfast