A browser extension that filters pseudo-brand junk out of Amazon. Buy from real, established brands, even when that means paying more.

Amazon is flooded with trademark-squat "brands" (SZHLUX, HORUSDY, LATTOOK, DOZAWA...): random strings registered at the USPTO purely to unlock Amazon Brand Registry, selling commodity goods with no company, no warranty, and no reputation behind them. Knockoff detects those listings and hides, dims, or labels them, right in the search results.

Install

Add to Chrome from the Chrome Web Store, or Add to Firefox from Firefox Add-ons.

Or load it unpacked for development:

1. Clone this repo
2. Open chrome://extensions
3. Turn on Developer mode (top right)
4. Click Load unpacked and select the repo folder

Works on every Amazon marketplace.

Safari

Safari requires the extension to be wrapped in a native app. Open safari/Knockoff/Knockoff.xcodeproj in Xcode, run the Knockoff scheme, then enable Knockoff in Safari → Settings → Extensions. For unsigned local builds, first check "Allow unsigned extensions" in Safari's Develop menu.

The Xcode project carries its own copy of the extension files; after editing the extension, run scripts/sync-safari.sh to update it before rebuilding.

How it works

Everything runs locally in a content script. No accounts, no tracking, no server round-trips on the shopping path. Each product tile's brand is resolved through this pipeline (first match wins):

#	Check	Verdict
1	Your allowlist	allowed, never filtered
2	Your blocklist	blocked, always filtered
3	Seed list of notorious pseudo-brands (data/flagged-brands.js)	flagged
4	Established Chinese-owned brands (data/chinese-major.js)	known, or flagged if you enable that setting
5	~5,000 established brands (data/known-brands.js + the community allowlist in data/community-brands.js, refreshed daily from api.knockoff.shopping/brands)	known
6	Name heuristics (see below)	flagged / suspect / unknown
-	No brand at the front of the title at all	unbranded

Name heuristics

Unknown brands are scored on the linguistic signature of trademark-squat names: ALL-CAPS 5–9 character strings, vanishing vowel ratios, unpronounceable consonant runs, un-English letter pairs, non-Latin characters, random iNternal caPitalization. High scores are flagged, mid scores suspect. The known-brands list always vetoes the heuristics: plenty of real brands (ASICS, RYOBI, HOKA) would otherwise look suspicious. Scoring lives in src/detector.js and is deliberately readable, and tuning it is a great first contribution.

Filter levels

Level	Filters
Relaxed	Known pseudo-brands + your blocklist
Standard (default)	+ suspect-looking names + unbranded listings
Strict	+ anything not on a known-brands list (allowlist-only)

Actions

Filtered items can be hidden (with a floating pill showing the count and a one-click reveal), dimmed (fade + desaturate, restore on hover), or just labeled. Every badge is clickable: trust the brand, block it, show the item once, or report a misclassification.

Product detail pages get a verdict chip next to the brand byline. The page is never hidden out from under you.

Reporting misclassifications

The badge menu has one-click reporting ("this is junk" / "this is a real brand"). Reports go to a tiny Cloudflare Worker backed by D1 (report-worker/) and are reviewed by hand to improve the bundled lists. No PII: the payload is brand, verdict, ASIN, marketplace, and extension version; reporter IPs are stored only as salted hashes for rate limiting. If no endpoint is configured the extension falls back to opening a prefilled GitHub issue.

Deploying your own endpoint is four commands; see the header of report-worker/worker.js.

Contributing

The easiest, highest-value contributions are brand list fixes; see CONTRIBUTING.md. There is no build step; the extension is plain JavaScript, loadable directly from the repo.

manifest.json             MV3 manifest
data/known-brands.js      curated established brands (edit this one!)
data/chinese-major.js     established Chinese-owned brands (toggleable)
data/flagged-brands.js    seed blocklist of notorious pseudo-brands
data/generic-words.js     common title words, for unbranded detection
data/community-brands.js  bundled community allowlist snapshot (generated, don't edit)
src/detector.js           detection engine (pure logic, no DOM)
src/content.js            page scanning, badges, actions, in-page control panel
src/background.js         toolbar button → panel toggle (or options page)
options/                  settings page (rules, allow/blocklist)
report-worker/            Cloudflare Worker: reports, curation, brand-list API
safari/                   Xcode wrapper app for Safari (macOS)
site/                     knockoff.shopping landing page (static, Cloudflare)
store-assets/             Chrome Web Store images + the HTML frames that render them
scripts/                  maintenance scripts

Known limitations

• Mixed-case gibberish ("Geinxurn", "Mulwark") scores below the suspect threshold at standard level; Strict mode catches it. A bundled character bigram model would fix this properly; PRs welcome.
• Seller country-of-origin lookup (fetching seller profile addresses) is deliberately not implemented: it costs two rate-limited page fetches per product and Amazon 503s aggressive scrapers. The name-based approach needs zero network calls.
• Carousels and a few exotic tile layouts aren't scanned yet (TILE_SELECTORS in src/content.js is the extension point).
• Non-English stores are best-effort. Brand lists and the product-page chip work everywhere, but the name heuristics are English-tuned, so an unlisted local brand can slip through. Non-Latin listings (Japanese, Arabic) are skipped rather than mis-filtered, so nothing breaks on any marketplace.

Prior art

Research that shaped this design: AmazonBrandFilter (allowlist approach; its MIT-licensed community list seeded Knockoff's own), SoldBy (seller-country lookup and its rate-limit lessons), and The Markup's Amazon Brand Detector. Knockoff's contribution is combining a community allowlist with a heuristic scorer, with the allowlist as veto.

License

FSL-1.1-MIT. Code converts to MIT after two years.