Firefox chief Ajit Varma explains how Mozilla is betting on privacy, optional AI tools, and its nonprofit structure to compete against browsers from Google, Apple, and Microsoft.

Firefox is the browser that, statistically speaking, more people remember using than use today. Its market share in most countries is now just a sliver of what it once was. In 2011, it held more than a quarter of the U.S. desktop market.

That many former users still remember it fondly may be a point of pride for the San Francisco-based nonprofit foundation behind the browser that broke Internet Explorer’s mediocre monopoly. But nostalgia alone doesn’t pay for the continued development of Firefox’s in-house Gecko rendering engine, along with versions of the browser for every major desktop and mobile operating system.

“Anyone who was using the internet 15 years ago was probably using Firefox at some point,” says Ajit Varma, head of Firefox at Mozilla, speaking on the sidelines of Web Summit Vancouver.

His theory for why Firefox users become former Firefox users is simple: The largest browser developers benefit from inertia, and from avoiding the kinds of mistakes that once pushed Internet Explorer users toward alternatives. “There’s just never a reason to question the default because it’s kind of just good enough,” he suggests.

A choice in AI tools, including none of them

Of course, Mozilla isn’t alone in adding AI features to its browser. But unlike Apple, Google, and Microsoft, it isn’t weaving a proprietary AI assistant throughout the browsing experience. “We’re not an AI company,” says Varma. “That’s a really great place for us to be in, where we’re just trying to create the best browser and [considering] how does AI improve those browser paths.”

Firefox’s most prominent AI implementation so far is an optional sidebar that connects users to a range of chatbots: Google’s Gemini, Microsoft’s Copilot, OpenAI’s ChatGPT, Anthropic’s Claude, and the French startup Mistral’s Le Chat. (Most people haven’t tried it. Varma says Mozilla’s telemetry shows that just 5% of users have experimented with the sidebar.)

Another opt-in feature uses on-device AI to suggest and name tab groups. Firefox’s settings menu also includes an “AI Controls” pane with a “Block AI enhancements” toggle that hides all of these tools entirely.

Mozilla is now slowly rolling out a more ambitious AI feature: Smart Window, an on-device browsing assistant that can summarize web pages and provide recommendations based on a model of the user’s interests generated from browsing history. “We’re trying to do everything as locally as possible,” Varma explains. “We don’t send to the cloud unless you explicitly ask a query.”

He’d like to see AI go farther in offering browsing help in response to plain-language queries—for example, finding every tab about an upcoming trip to Japan and putting them in a group to share with a family member, or having an agent do a daily search for suitable job listings. “These are all things that we’re looking at as the positive side of AI,” he says, noting later that some of these AI services might have to come with a price tag for users.
Privacy, please

Firefox’s emphasis on employing on-device AI models instead of enlisting cloud services—most notably, if not most visibly, in its language-translation feature—fits with Mozilla’s longstanding focus on privacy. The company began blocking tracking cookies by default in 2019, following Apple’s lead. (Chrome, meanwhile, still defaults to allowing ad networks, including Google’s own, to track users across the web.)

Firefox now also blocks social-media trackers and fingerprinting, a technique that attempts to identify users based on the unique characteristics of their browser and device setup. It has also introduced containers, a middle ground between standard browsing and private windows that keeps isolated tab groups separate from the rest of a user’s browsing activity while still allowing them to persist across sessions.

The newest addition to Firefox’s privacy toolkit is a free built-in VPN (subject to a 50 GB monthly usage cap) to cloak your browsing from the operator of your internet connection by routing it through proxy servers run by Mozilla’s partner Fastly. The feature reflects a broader shift in the browser wars: Privacy tools once reserved for power users willing to pay for third-party services are increasingly being folded directly into mainstream browsers themselves. “We have tens of thousands of people who are signing up every day,” Varma says, declining to provide a total figure. “It’s probably the most successful feature we’ve launched in a couple of years.”

Mozilla has spent the past few years pulling back from sprawling side projects and refocusing its attention on Firefox itself. The company still resells the standalone VPN service from the Swedish firm Mullvad, but it has wound down other attempts to build subscription products, including the Pocket read-it-later bookmarking service. “In the past, Mozilla tried some really ambitious projects that were very noble in spirit,” Varma says. “We’re almost getting back to our roots; how do we just make Firefox the best browser?”

Mozilla itself, however, continues to depend heavily on Google’s paying to be the default search engine in Firefox. “Revenue diversification is important to us, for a lot of reasons,” Varma says, echoing previous statements by prior Mozilla executives. He cited the new-tab screen, filled with suggested news and entertainment sites and the occasional ad, as one revenue-improvement opportunity.