September 16, 2026
AI in Firefox will become multilingual: Smart Window will add Mistral Small 4
On September 16, 2026, Mozilla selected Mistral Small 4 for the Smart Window beta in Firefox. The model will be added for beta users in the US and Canada, while access will expand in France with official French-language support enabled.
Smart Window let users choose one of 3 models or connect their own, with no fixed provider. **Now.** Mozilla will add Mistral Small 4 after evaluating its multilingual performance. Smart Window groups tabs, shows history, compares options, summarizes articles, and builds plans from guides, reviews, and open tabs.
The feature is available only on desktop. To try it, download the latest version of Firefox, reopen the Smart Window page, copy the suggested site, and paste it into the browser. Mozilla says it does not store chats, use them for training, or sell data, and chat content is shared only at the user's choice. Memory is stored on the device: it can be reviewed, deleted, or turned off.
Mozilla plans to expand Smart Window in Europe later in 2026.
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