What to know

  • Mozilla earned $570 million in 2024, with 85% coming from Google search revenue sharing deals.
  • Mozilla CFO Eric Muhlheim testified that Firefox and its Gecko engine could face severe constraints without these search partnerships.
  • When Mozilla previously switched from Google to Yahoo as default search (2014-2017), users either manually switched back to Google or abandoned Firefox entirely.

Mozilla executives are sounding the alarm about Firefox's future as the U.S. Department of Justice (DOJ) antitrust case against Google threatens to disrupt the search revenue partnerships that keep the independent browser afloat.

Mozilla's Chief Financial Officer Eric Muhlheim testified on May 2, 2025, in the U.S. v. Google search trial, revealing critical details about Mozilla's financial dependence on Google. According to his testimony, Mozilla earned $570 million in revenue last year, with approximately 85% coming from Google.

This revenue stream exists because Mozilla receives a share of ad revenue generated when Firefox users conduct searches through Google, which is currently the default search engine in the browser.

The DOJ has been pushing for remedies that would prevent Google from paying browser makers like Mozilla and Apple to maintain Google Search as the default search engine, flagging these practices as anti-competitive.

"Firefox is an independent browser — we don't have our own OS, devices, or app store," Muhlheim stated during proceedings. Without search revenue, "Mozilla and other small, independent browsers may be forced to scale back operations and cut support for critical projects like Gecko."

Gecko is particularly significant as it's the only remaining browser engine competing with Google's Chromium and Apple's WebKit. Its potential demise would further reduce competition and diversity in the browser market.

Mozilla has firsthand experience with the consequences of moving away from Google. Between 2014 and 2017, Mozilla switched Firefox's default search engine from Google to Yahoo in an effort to support search competition. The results were disastrous.

"Firefox users found Yahoo's search quality lacking and some switched to Google search while others left the Firefox browser altogether," Muhlheim explained in his testimony.

Mark Surman, President of Mozilla, has argued that the DOJ's proposed remedies could have unintended consequences: "The big unintended consequence here is the handing of power from one dominant player to another... while shutting out the smaller, independent challengers that actually drive browser innovation."

Mozilla maintains that its approach to search is built around user choice, with Firefox offering more than 50 search providers across over 90 locales. The organization argues that any remedies should ensure small and independent browsers are not harmed.

"Without this, we risk trading one monopoly for another, and the vibrant, people-first web we've spent decades fighting for could begin to fade," Surman warned.

The case highlights the complex relationship between search and browser competition, with Mozilla caught in the middle as it relies on revenue from the very company whose dominance the DOJ seeks to curtail.

Via: The Verge