Mozilla's Smart Window bets that opt-in AI is a feature, not a concession

Mozilla is rolling out Smart Window, an opt-in AI browsing mode in Firefox built on a partnership with search provider Exa, starting in the United States and Canada ^[1][2]. The bet is unusual in a market where assistants arrive switched on: the feature appears only to people who turn it on, and they can toggle it off temporarily or disable it entirely at any point ^[5].

Smart Window puts a chat panel alongside ordinary browser content, answering questions the way ChatGPT or Claude would, but with access to a user's open tabs and "memories" built from browsing history ^[6]. Ajit Varma, head of Firefox, frames it as choice rather than default: "Some people definitely want AI, some people don't, and so, what we're looking at is really choice" ^[15]. He also said Mozilla will not "upsell a user to ever use it again" if they decline ^[16].

The Exa deal supplies the web knowledge. When a question needs current information, the model writes a search query, sends it to Exa's API, and composes an answer from the response, now with source links attached ^[3][4]. Exa says it crawls more than 500 billion web addresses with its own models and databases ^[20], and it already powers search for Cursor, Cognition, and HubSpot ^[21]. In May it raised $250 million led by Andreessen Horowitz at a $2.2 billion valuation ^[22]. Both companies say neither retains the data sent during those searches ^[8].

The privacy posture is the product's argument. Mozilla says it does not retain chat transcripts or train on interactions unless users opt into specific programs, and accumulated memories can be deleted from settings ^[9]. Firefox AI product manager Steve Truong said the selectable models run under zero-data-retention contracts, meaning third parties process prompts in memory and store nothing for training, advertising, or human review ^[10]. Users pick their model from Google's Gemini 3.1 Flash Lite, OpenAI's oss-gpt-120b, Alibaba's Qwen3-235B-A22B-Instruct-2507, or a local model of their own ^[11]. Varma casts local and regional options as "digital sovereignty" ^[13].

Beyond chat, Smart Window can suggest tab groups, close duplicates, and surface visual previews of pages from history through natural-language search ^[18]. Mozilla says beta users reported it helped them hold their train of thought ^[25], and planned updates include recent-journey surfacing and AI autofill for forms ^[7]. There is no date for leaving beta ^[14]. The feature was first announced last year as "AI Window" ^[19], and Mozilla has since added an AI Controls section to settings ^[17].

The context is a graveyard of more aggressive attempts. OpenAI launched a browser called ChatGPT Atlas last year and discontinued it, folding web access into ChatGPT itself ^[23]. Mozilla, the maker that helped break Internet Explorer's dominance in the 2000s ^[24], is wagering the opposite of default-on: that some users will choose an assistant precisely because they had to switch it on themselves.

What to watch is whether opt-in rates justify the engineering, and whether the promised agentic features, which Mozilla is testing to let the AI tweak settings or generate embeddable widgets and extensions, arrive without eroding the restraint it is selling ^[12].