Lumo AI Assistant

Lumo is an open-source, privacy-focused AI assistant developed by Proton AG, the Swiss company behind Proton Mail and Proton VPN. Launched on July 23, 2025, Lumo is designed to prioritize user privacy by operating without logs, employing zero-access encryption, and not using user data for model training. It offers features such as document summarization, code assistance, email rewriting, and file analysis. Lumo is accessible via web and mobile apps for iOS and Android, with a premium subscription (Lumo Plus) offering additional features like unlimited chats and extended history. The service runs on open-source AI models like Mistral's Nemo and Nvidia's OpenHands 32B, operating from European data centers controlled by Proton AG. Users' questions and responses are not used to train future versions, ensuring that private information remains confidential. Lumo is available for free at lumo.proton.me and does not require a Proton account when accessed. However, if you have a Proton account, your chat history can be saved using the company's zero-access encryption across all your devices. For power users, Lumo Plus costs $12.99 per month and removes limits on chats and file uploads.