Frequently asked questions

By Josh Pigford · Updated July 15, 2026

Everything people ask before installing Knockoff: what it does, what it sends and what it never touches, and where its judgment ends. If your question isn’t here, email [email protected].

The basics

What is Knockoff?

A free browser extension that filters trademark-squat pseudo-brands out of Amazon search results. On every search page it checks each listing’s brand against a register of 5,500+ established brands (refreshed daily), scores unknown names against the linguistic signature of pseudo-brands, and hides, dims, or labels the junk. Your call which. What’s left is brands with a reputation to lose.

Is Knockoff free? What’s the catch?

Yes, free: no accounts, no premium tier, no trial clock. There’s also no catch of the usual kind, because nothing the extension sends is tied to you, so there’s nothing to sell.

Is it safe?

Is the Knockoff extension safe and legit?

It’s about as checkable as an extension gets. It asks for two browser permissions up front (storage, to remember your settings, and scripting, to run its own bundled code on the shops it supports). Checking marketplaces beyond Amazon is opt-in, and turning it on asks for one more: your browser calls it access to all websites, because that is the only label it has. Knockoff only ever runs on the shopping sites it supports, and ships as plain unminified JavaScript with no build step, so the code your browser actually runs is open to inspection in the extension folder. Your browser also shows a data-collection label covering the two features that send anything; that’s answered below. Over 100,000 people run it across Chrome and Firefox, and it’s been covered by CNET, Gizmodo, 404 Media, and Lifehacker.

Does Knockoff track what I shop for?

Nothing is tied to you: no account, no profile, and no IP stored beside anything. But a flat “no” would be too glib. Two features send something, and both are on unless you turn them off. Seller country sends seller IDs, so we can show where a seller is based. Help pick US alternatives sends the product when you open an Amazon product page, so we know which products people want US alternatives for, and which unknown brands keep appearing on marketplaces the filter can’t read yet (a human reviews those for the junk list). A stored row says “this product was viewed N times” and nothing about who viewed it. The same switch covers Etsy: on an Etsy listing page it sends the listing’s own public signals (shop, made-by label, sales, ships-from) so independent sightings can corroborate or clear a listing, and looks up (by listing ID alone) whether corroborated sightings plus our catalog-image check flagged the listing you’re on — on results pages, the same check runs for the listing IDs shown, again IDs alone, to badge flagged tiles. Both are switchable in the extension’s options. Your searches and purchases never leave your browser. The privacy policy lists every call.

Why does my browser say Knockoff collects browsing activity?

Because the stores only offer broad labels, and the honest one is broad. Firefox lists “Browsing activity” and “Website content”; Chrome’s listing says “Web history” and “Website content”. Both are store vocabulary for the same two features above: seller country sends seller IDs, and “Help pick US alternatives” sends the product pages you open — the ASIN, title, and brand on Amazon; the listing’s public signals on Etsy. Neither store has a narrower label for “the product you’re looking at”, so we declare the broad one rather than under-declare.

It doesn’t mean what it sounds like. Knockoff holds no history permission and has no access to your browsing history. It runs only on the shopping sites it supports, so it never sees the other sites you visit, your searches, your orders, or anything you type into a page. Both features switch off in the extension’s options, and the filtering works without them. The privacy policy lists every call by name.

How it works

How does Knockoff decide what’s a knockoff?

Three signals, in order. A register of 5,500+ established brands: names on it are left alone. A linguistic score for unknown names, tuned to the signature of trademark-squat pseudo-brands (ALL-CAPS strings, vanishing vowels, improbable consonant runs). And a community list built from user reports, which reaches every install within a day. Verdicts are heuristics plus lists, not ground truth. That’s why every one is one click from being overridden.

What happens when it flags a brand I trust?

You override it. Mark the brand as trusted and it’s never touched again; your personal lists beat every other signal. If you think the verdict is wrong for everyone, the one-click report sends it in for review, and accepted fixes reach all installs within a day, no extension update needed.

Are Chinese brands automatically flagged?

No. Established companies that happen to be Chinese, like Anker or DJI, are on the known-brands register and treated like any other real brand. The line Knockoff draws is disposability, not geography: a company with a website, a support line, and a reputation to lose passes; a registered-yesterday trademark on generic goods doesn’t.

Does it slow Amazon down?

The check is a lookup against a local list plus a string score, done in your browser as results render. Nothing on the shopping path waits on a server, because nothing on the shopping path makes a network call.

What it won’t do

Does Knockoff detect fake reviews?

No, and it doesn’t try to. Knockoff never reads reviews; it judges the brand behind the listing, in search results, before you click. For per-product review grading, pair it with a review checker. Our Fakespot alternatives guide covers the options honestly, including tools that aren’t us.

Can it tell me if a product is counterfeit?

No. Counterfeits and pseudo-brands are different problems. A counterfeit fakes someone else’s trademark (a “Nike” that isn’t Nike); a pseudo-brand is a legally registered trademark on generic goods. Knockoff filters the second kind. Nothing in a search results page can authenticate the first.

Does it track prices or find deals?

No. No price history, no alerts, no coupons. One job.

Install and compatibility

Which browsers does it work in?

Chrome from the Chrome Web Store, Firefox (desktop and Android) from Firefox Add-ons, and Safari on Mac, iPhone, and iPad from the App Store (macOS 11 or iOS 15 and later). Other Chromium browsers such as Edge, Brave, and Vivaldi install from the Chrome listing. Safari works a little differently from the rest: it installs as an app, and you switch the extension on in Safari’s settings afterward.

Does it work outside amazon.com?

Yes. It runs on 23 Amazon marketplaces, from amazon.co.uk and amazon.de to amazon.co.jp and amazon.com.au.

Does it hide sponsored listings too?

Yes, as a separate toggle. Sponsored placements disappear from your results along with the pseudo-brands. There’s a short guide if you only want that part.

Something’s broken. Where do I get help?

Email [email protected]; mail is read and answered. For a wrong verdict, skip the email: the report button on the badge is faster.