Free and extensible Web browser

Firefox made by Mozilla is the most popular free software web browser. Browsers are highly complex programs, and being popular means that security bugs are more likely to be noticed and fixed than in browsers that receive less usage and therefore less scrutiny. Firefox can also be enhanced by installing browser extensions that provide countermeasures against online tracking and advertising. However, Firefox also introduces a host of ethical pitfalls in the form of anti-features.


Even though Firefox is free software it nevertheless contains various anti-features:

Further privacy enhancement and hardening of the browser are possible through Firefox’s about:config page. See PrivacyTools’s guide for a more in-depth rundown of options.


There are very few alternatives to Firefox that respect your freedom and privacy. Some such alternatives, all based on Firefox, include:

GNU IceCat

Free and extensible Web browser based on Firefox

Tor Browser

Free and extensible browser for use with the Tor anonymity network


A fork of Firefox focused on privacy, security, and user freedom

Browser extensions (also known as browser add-ons) are small programs that extend the functionality of your Web browser, including enhanced privacy features.

Back to top