Is FBA Calculator for Amazon FBA Sellers - Free safe?

FBA Calculator for Amazon FBA Sellers accepts a login API key from any postMessage sender on Amazon pages, with no origin check.

After you click the extension's login button, its content script installs a window.onmessage handler on every open Amazon tab that accepts a marketgap.pro API key from any message starting with a fixed prefix, without checking who sent it. That key is stored and reused as the Authorization value on all later requests to marketgap.pro, so a page that can reach the same window object can substitute its own key and redirect your product-research data (viewed ASINs, Amazon site) to an account it controls.

Part of this rating comes from analysis signals we haven't published as detailed findings yet.