Simple Blocker is a lightweight Firefox extension designed to enhance online security by blocking unwanted URLs based on regular expressions. This subscription-based tool features two filter modes: Blacklist and Whitelist. Users can easily customize their browsing experience by inputting multiple regular expressions, each separated by a newline, to effectively manage which URLs are blocked or allowed.

The extension includes a debug mode that allows users to view blocked URLs directly in the browser console, providing transparency and control over the blocking process. With its straightforward interface and functionality, Simple Blocker serves as a practical solution for users seeking to maintain privacy and reduce spam while browsing the web.