The Online Seller Addon is a Firefox extension designed specifically for Amazon sellers, providing a free stock counter that allows users to check product inventories effortlessly. With unlimited daily product checks, this addon enhances the shopping experience by displaying inventory counts for various offers directly on Amazon listings. It operates seamlessly across all Amazon domains, ensuring that sellers can monitor their competition without hassle.

Installation is straightforward; users simply need to add the extension to their browser without any need for account creation or signup. Once installed, checking stock levels is as easy as visiting a product detail page on Amazon and activating the addon. The user-friendly interface allows for quick access to essential inventory data, making it a valuable tool for anyone engaged in online selling.