Started in 2011 by 16-year-old Alex Kontos to provide a 64-bit Firefox build when Mozilla didn't offer one. Waterfox evolved to focus on privacy and legacy extension support, survived an acquisition by ad company System1, and regained independence in 2023.
Waterfox is built on Firefox ESR (Extended Support Release) using the Gecko rendering engine. It disables telemetry, Pocket integration, and Sponsored Tiles by default. The Classic branch maintained XUL/XPCOM legacy extension support after Firefox dropped it. Modern Waterfox tracks recent Firefox ESR releases with privacy-focused configuration changes.
The origin story of Waterfox is almost too good to be true. In March 2011, Alex Kontos — a sixteen-year-old student — was frustrated that Mozilla didn't provide an official 64-bit build of Firefox. So he compiled one himself, called it Waterfox, and uploaded it to SourceForge. Within a week, it had 50,000 downloads. A hobby project by a teenager had found a genuine gap in the market.
As Firefox eventually shipped its own 64-bit builds, Waterfox's raison d'être shifted. Kontos repositioned the browser around privacy and user choice — disabling telemetry by default, supporting legacy XUL/XPCOM extensions long after Firefox dropped them with the Quantum overhaul in 2017, and offering a more conservative approach to UI changes. For users who felt Firefox was becoming too Chrome-like or too aggressive with data collection, Waterfox became a refuge.
In December 2019, Waterfox was acquired by System1, an advertising technology company. The announcement sent shockwaves through the privacy-focused user base — a browser marketed on privacy, now owned by an ad company? Kontos maintained that System1 would not compromise Waterfox's privacy stance, but trust was damaged. The acquisition also prompted some users to migrate to other Firefox forks like LibreWolf.
In July 2023, Kontos announced that Waterfox had returned to full independence. The browser was once again a one-person passion project with community support, free of corporate entanglements. Modern Waterfox is built on recent Firefox ESR releases, maintaining the Gecko engine while offering its own privacy-focused defaults and UI preferences.
Waterfox occupies a peculiar niche: it's too close to Firefox to attract users seeking a fundamentally different browser, but different enough to serve those who want Firefox's rendering engine without Mozilla's telemetry decisions and rapid UI churn.
16-year-old Alex Kontos releases Waterfox as a 64-bit Firefox build; gets 50,000 downloads in a week
macOS build introduced with Waterfox 38.0
Firefox Quantum drops legacy extensions; Waterfox maintains support for XUL/XPCOM add-ons
System1, an advertising company, acquires Waterfox
Alex Kontos reacquires Waterfox, restoring independence from System1
Waterfox demonstrated that there is persistent demand for a Firefox variant focused on privacy and user control, even if that demand is niche. Its survival through a controversial acquisition and return to independence showed the resilience of solo-maintainer projects when the maintainer is sufficiently dedicated.
More broadly, Waterfox is part of a family of Firefox forks (alongside Pale Moon, LibreWolf, Tor Browser, and others) that collectively signal dissatisfaction with Mozilla's direction. While no single fork has threatened Firefox's position, together they represent a meaningful constituency of users who want Gecko without Mozilla's editorial decisions.