Mozilla Tests an Opt-In AI ‘Smart Window’ in Firefox

Mozilla is testing a new “Smart Window” in Firefox: a separate, optional window where users can chat with an AI assistant of their choice while they browse. The company is inviting users to join a waitlist to try it first, and the feature remains off unless a user turns it on. The Smart Window sits alongside Firefox’s Classic and Private modes. Mozilla says users decide when, how, or whether to use AI at all, and can switch it off if it is not for them. In its announcement, Mozilla described the feature as “user-controlled” and said it is being built in the open, with feedback from early testers. Mozilla is also drawing a contrast with browsers made by AI companies. Its pitch is that those products often force a hard choice: use AI all the time, or not at all. Firefox, Mozilla argues, keeps the user in control. “In Firefox, you’ll never be locked into one ecosystem or have AI forced into your browsing experience. You decide when, how or whether to use it at all,” the company said. Smart Window expands on AI features Mozilla already ships, including the AI chatbot in the desktop sidebar and Shake to Summarize on iOS. Browser AI has also become a privacy battleground, and open-source code is what allows outside researchers to verify the claims these tools make. Brave has pushed its own LEO assistant, built with Anthropic, as a privacy-first alternative. Other companies are taking a different route, building AI-centric browsers such as Perplexity Comet, Microsoft Edge, and Opera Neon. OpenAI has killed its own Atlas browser to focus on developing a more general-purpose app. Google has also tried to enhance its browser with AI, silently downloading a model that runs locally. Mozilla is trying to broaden Firefox’s appeal without walking away from its privacy-first roots: offer the assistant, but make the off-switch the main draw. The idea ties back to the Project Nova redesign, which gave Firefox a single control to disable every AI feature at once. Mozilla says AI should be “open, accessible, and driven by choice.” The Smart Window waitlist is open at firefox.com/ai.