The best open source alternative to Mozilla Firefox is Zen Browser. If that doesn't suit you, our users have ranked more than 100 alternatives to Mozilla Firefox and loads of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Mozilla Firefox are Brave, Tor Browser, LibreWolf and Helium Browser.
Experience a privacy-focused, open-source browser rich with features like vertical tabs, Split View, Zen Glance, and extensive security protocols. Built on Firefox, it's currently in beta, emphasizing privacy and adaptability, with future plans for horizontal tabs.
Spain
EU
Fast, secure browser integrating ad and tracker blockage, privacy features, and VPN. Offers seamless performance with data and battery optimization, faster loads by blocking pop-ups and ads. Safeguards user privacy with tracking protections and built-in brave search.
United States
Experience true privacy online with a portable browser offering built-in proxy, encryption, and tracker blocking. Navigate without revealing location or browsing data, enjoying ad-free, secure surfing across platforms like Windows, Mac, Linux, and Android with no installation hassle.
United States
LibreWolf is a community-maintained, privacy and performance-enhanced browser forked from Firefox, independent of Mozilla. It uses over 500 settings to limit telemetry, offers an Extensions Firewall, supports all major systems, and is developed free from corporate influence.
Chromium browser with open-source ad, tracker, and cryptominer blocking by default, zero tracking, customizable privacy controls, proxy-anonymized extension downloads, split view, and efficient, unobtrusive interface for full extension compatibility.
United States
Open-source browser project offering strong security, fast performance, and stability with broad support for Windows, macOS, Linux, and Android, extensive customization, frequent security updates, minimal default tracking, and foundation for multiple browsers.
United States
Utilize Waterfox for a high-speed, private browsing experience on 64-bit systems. Built on Firefox, it taps into Intel's C++ compiler for optimal performance, supports legacy extensions, allows full customization, and blocks ads by default, ensuring utmost control and security.
United Kingdom
Open-source browser based on Firefox, combining advanced privacy and tracking protection with a Chromium-inspired interface, cross-platform support, customization options, compatibility with Firefox extensions, regular updates, efficient performance, and multilingual support.
Japan
The Mullvad Browser is a privacy-focused web browser developed in a collaboration between Mullvad VPN and the Tor Project. It’s designed to minimize tracking and fingerprinting. You could say it’s a Tor Browser to use without the Tor Network.
SwedenEU
Open-source web browser eliminates Google integration, disables background communications, strips non-free binaries, and includes privacy-focused patches and scripts for full transparency, control, and compatibility with Chromium extensions across major platforms.
IronFox is a fork of DivestOS's Mull Browser based on Firefox. Our goal is to continue the legacy of Mull to provide a secure, hardened and privacy-oriented browser for daily use.
Browser using the Gecko layout engine to render web pages, which implements current and anticipated web standards.
