Proton, the Swiss company behind encrypted email service Proton Mail, has launched its first stand-alone artificial-intelligence assistant. The chatbot, called Lumo, became available on 23 July and is intended as a privacy-centric alternative to mainstream products such as ChatGPT, Google Gemini and Microsoft Copilot. Lumo can summarise documents, generate code, draft emails and answer web queries. The service runs exclusively on open-source language models—including Mistral’s Nemo and Small 3, Nvidia’s OpenHands 32B and the Allen Institute for AI’s OLMO 2 32B—that are hosted in Proton-controlled European data centres. All conversations are protected with "zero-access" end-to-end encryption, Proton says, meaning neither the company nor third parties can read or retain user messages; chats are also excluded from training future models. A Ghost mode deletes exchanges when a session closes, and web search is disabled by default for added confidentiality. Anyone can try Lumo through a web client or dedicated iOS and Android apps without opening an account, though usage is capped. Registered users gain an encrypted chat history and limited file uploads, while a paid Lumo Plus plan costing US$12.99 a month removes chat limits, extends history, and supports larger files. Proton Visionary and Lifetime subscribers receive the Plus tier at no extra charge. Chief Executive Officer Andy Yen said the launch is part of Proton’s effort to offer AI tools that "put people ahead of profits" and resist what he calls "surveillance capitalism" practiced by Big Tech.