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Firefox keeps a hidden configuration file, user.js, that lets you tweak hundreds of internal settings before the browser launches. Editing it by hand is tedious and risky, which is why pre-built collections exist, like arkenfox and Betterfox.

The difference between them matters. Arkenfox goes for maximum hardening: great if you’re willing to accept occasional broken sites in exchange for a smaller attack surface. Betterfox takes a different approach, the minimal effective dose: change only what’s worth changing, without disrupting everyday browsing.

The project splits into four modular components: Fastfox for performance, Securefox for privacy and security, Peskyfox to strip away UI clutter, and Smoothfox for smooth scrolling. The final user.js file integrates the settings considered essential from all four sections.

Installation takes minutes. Download the user.js file from the project page, open Firefox, type about:profiles in the address bar, and click Open Folder under the active profile’s root directory section. Drop the file there. When you restart the browser, the settings are live. The docs recommend creating a backup profile first, just in case you want to revert.

Version 149.0, released recently, is a maintenance update that fixes a graphics bug on macOS and Linux that could cause visual glitches after upgrading to Firefox 149. Users on those platforms should manually reset the gfx.webrender.layer-compositor parameter to false via about:config after updating.

The project is actively maintained, has over 10,000 GitHub stars, and is already integrated in various forms into several Firefox forks including Zen Browser, Waterfox, and Floorp.

If you want a Firefox that’s a bit less out-of-the-box without diving into security researcher territory, Betterfox is a solid starting point. Pair it with an encrypted DNS service like NextDNS for private browsing and you’re set without much extra effort.