Proton, the company behind the encrypted email service Proton Mail, has launched an AI assistant aimed at preserving user privacy. The new chatbot, called Lumo, can summarize documents, generate code, write emails, and more, while storing data locally on users’ devices.

Proton says it will protect this information using “zero-access” encryption, which grants users an encryption key that only they can use to view their content, preventing third parties, including Proton, from accessing the information. This helps ensure that Proton can’t share user data with advertisers or governments, or use it for training large language models, Proton says.

Though Lumo comes with the ability to search the web, Proton turns this feature off by default to “give users maximum privacy.” If users enable the feature, Lumo will search the web for answers using “privacy-friendly” search engines. Additionally, Proton says Lumo can analyze uploaded files, but it doesn’t save any of its information. Users can link Proton Drive files to Lumo as well, which are supposed to stay end-to-end encrypted when interacting with the chatbot.

Proton positions its AI chatbot as an alternative to the ones offered by larger companies, like OpenAI’s ChatGPT, Meta AI, Google’s Gemini, and Microsoft Copilot. “Big Tech is using AI to supercharge the collection of sensitive user data to accelerate the world’s transition to surveillance capitalism,” Andy Yen, the CEO and founder of Proton, says in the announcement. “Our vision for Lumo is AI that puts people ahead of profits.”

Lumo is powered by several open-source large language models that run on Proton’s servers in Europe, including Mistral’s Nemo, Mistral Small 3, Nvidia’s OpenHands 32B, and the Allen Institute for AI’s OLMO 2 32B model. The AI chatbot will field requests through different models depending on which is better-suited for the query. “For instance, programming-related questions are handled by OpenHands, which specializes in coding tasks,” Proton spokesperson Betsy Jones tells The Verge.

You can access Lumo now by heading to lumo.proton.me, or downloading the Lumo app for iOS and Android. Users who don’t have an account with Lumo or Proton can only ask the chatbot a “limited number” of questions each week, and they won’t be able to access their chat histories. Meanwhile, users with a free account can view an encrypted chat history, upload small files, and favorite a limited number of chats. There’s also a $12.99-per-month Lumo Plus plan for access to unlimited chats, extended encrypted chat history, unlimited favorites, and the ability to upload large files.