Alternatives to Mercury
A Firefox fork with compiler optimizations and privacy patches taken from LibreWolf, Waterfox and GNU IceCat. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
Mercury
A Firefox fork with compiler optimizations and privacy patches taken from LibreWolf, Waterfox and GNU IceCat.
Replacements
Listings that take over the same core job as Mercury.
LibreWolf
A Firefox build with the privacy settings already turned up and uBlock Origin included.
LibreWolf is one of the projects Mercury borrows privacy patches from, shipping uBlock Origin, strict tracking protection and Resist Fingerprinting, and clearing cookies on close by default.
Waterfox
A Firefox build with telemetry stripped out, ad blocking and encrypted DNS turned on from the start.
Waterfox, another source of Mercury's patches, strips telemetry from the build and turns on ad blocking and encrypted DNS, and also offers an Android build.
Firefox
The main browser not built on Chromium, with tracking protection turned on by default.
Firefox is the upstream Mozilla release, so updates arrive first and it runs on Android and iOS, though without Mercury's compiler optimizations or extra privacy patches.
Floorp
A Firefox build from Japan with vertical tabs, workspaces, split view and web panels already wired in.
Floorp keeps the Firefox engine and add-ons while adding built-in vertical tabs, workspaces, split view and web panels, maintained by a small team rather than one developer.
Zen Browser
A Firefox build with vertical tabs, workspaces and split view, aimed at people who found Arc appealing.
Zen Browser is a Firefox build focused on an Arc-style layout with vertical tabs, workspaces and split view, including ARM64 builds, rather than on compiler optimizations.
GNU IceCat
The GNU Project's build of Firefox containing only free software, with added privacy extensions.
GNU IceCat, another patch source for Mercury, contains only free software and blocks nonfree JavaScript with LibreJS, but is Linux only and breaks many sites until scripts are allowed.
Mullvad Browser
Tor Browser's fingerprinting defences without the Tor network, built to sit in front of a VPN instead.
Mullvad Browser uses Tor Browser's fingerprinting defences without the Tor network, is meant to run behind a VPN, and requires macOS Sonoma or later.
Also worth comparing
These listings name Mercury as their own alternative, so the relationship runs both ways.
Firefox ESR
The Extended Support Release of Firefox, a long-term stable build intended for organisations.
Mercury is a compiler-optimized Firefox fork with privacy patches and a portable variant, but a single developer maintains it and updates can trail official Firefox releases.
Similar software
Related functionality, not a direct replacement.
Tor Browser
A hardened Firefox that sends every page through the Tor network, so the site sees an exit node instead of your address.
Pale Moon
Independent Firefox fork with the classic interface and XUL extension support.
IronFox
Hardened Firefox fork for Android, successor to DivestOS Mull.
Firefox Developer Edition
A pre-release build of Firefox for web developers, with the newest developer tools and platform features.
