Proton Lumo

Lumo is the confidential AI chat assistant from Proton, the company behind Proton Mail and Proton VPN. Mainstream assistants keep chat logs that can be read by the provider, used for training or handed to a third party. Lumo removes that exposure rather than promising not to look.

All conversations with Lumo are stored with zero-access encryption, so no one, not even Proton, can access them, and they are only accessible on your devices. Proton does not log chats, never uses the data to train AI models and cannot share it with third parties. The service is European and GDPR compliant, the company is based in Geneva, and Lumo's code is fully open source, so anyone can verify that it is private and secure.

The assistant itself does the ordinary work you would expect.

• Web search: current information retrieved and folded into an answer.
• Image generation: descriptions turned into images in seconds.
• Proton Drive files: files and folders linked from Drive and worked with in a chat.
• Projects and custom Lumos: saved contexts and tailored assistants on the paid tier.
• Guest access over Tor: anonymous use with no account at all.

Lumo runs as a web app and as iOS and Android apps. The free tier limits messages, history, image generation and use of the strongest model to one project, and Lumo Plus lifts those caps. The source lives in Proton's WebClients monorepo, beside Mail, Calendar, Drive and Pass, under version 3 of the GNU General Public License.