Overview
- Knockoff became publicly available for Chrome and Firefox in version 0.4.0 on Friday, July 10, 2026, and the code is published on GitHub for anyone to inspect.
- The extension flags listings by comparing sellers against a curated list of about 5,000 established brands and by spotting name patterns such as all-caps names, missing vowels, or unpronounceable letter strings.
- Pigford designed Knockoff to run entirely in the browser with no telemetry, no registration, and local processing so users' browsing data are not sent to a central server.
- Users can adjust strictness, maintain personal allow/block lists, hide sponsored results or filter sellers by origin, and a community-maintained filter database lets people report or correct classifications.
- Early tests and user reports show practical gains in surfacing dubious sellers but also clear limits: legitimate brands have been misflagged, some suspect listings go undetected, and the tool is under active development ahead of 1.0.