Proton Lumo is a privacy-first AI assistant developed by Proton AG, the Swiss company behind ProtonMail, Proton VPN, and Proton Drive. Launched in 2025, it is built entirely on open-source language models and designed to offer AI capabilities without compromising user privacy.

Key Features

• AI chatbot for conversations, document summarization, code generation, and text composition
• Zero-access encryption on all saved conversations — even Proton cannot read them
• Ghost mode that permanently erases conversations when closed
• Integration with Proton Drive for encrypted file uploads
• Built on open-source models including Mistral Small, Nemo, and OLMO
• Open-source web, iOS, and Android apps enabling external security verification

Privacy and Security

Proton Lumo runs exclusively from Proton's European data centers with no third-party AI providers involved. Zero-access encryption means Proton itself cannot read your conversations. No conversation logs are kept server-side, and user data is never used for model training. The service operates under Swiss privacy law, one of the strongest in the world, and is backed by the non-profit Proton Foundation.

Ideal For

• Privacy-conscious users who want the most secure AI assistant available
• Existing Proton ecosystem users looking for integrated AI capabilities
• Users who value open-source transparency and verifiable security
• Anyone who wants AI without any data collection or training on their conversations