Proton launches private AI chatbot Lumo

If you have ever hesitated to paste a sensitive legal contract, a medical diagnosis, or a private email draft into ChatGPT, you are not alone. Most big tech AI assistants treat your queries as training fodder or store them unencrypted on corporate servers.

Proton, the Swiss company behind encrypted services like Proton Mail and Proton Drive with over 100 million users, wants to fix that. The team just rolled out Lumo, a standalone AI assistant designed from scratch to keep conversations strictly confidential.

Zero-access encryption meets open-source models

Lumo approaches AI differently than the incumbents. Proton does not keep server-side logs of your chats. If you save your history, it is locked with zero-access encryption, meaning only your local device holds the key. Even Proton engineers cannot see what you asked.

Your inputs will never be used to train future language models. Furthermore, Proton avoided partnering with American or Chinese tech giants like OpenAI. Instead, Lumo runs open-source models hosted entirely inside Proton's own European datacenters, ensuring queries never hit third-party servers.

For features, Lumo includes web search, file analysis without retained uploads, and deep integration with encrypted files inside Proton Drive. It also features Ghost mode, which wipes your active chat session forever the moment you close the tab.

Anyone can try Lumo for free right now at lumo.proton.me or through new iOS and Android apps, with no account registration required. Logged-in Proton users get synced encrypted history, while heavy users can upgrade to a paid Lumo Plus plan for unlimited queries.

A 100 million euro flight from Switzerland to the EU

There is also a major geopolitical subplot to Lumo's launch. Proton announced it is investing over 100 million euros into physical infrastructure across the European Union, making Lumo its first product deployed directly within the bloc.

Proton is actually moving its primary infrastructure out of Switzerland. The company cited growing legal uncertainty around proposed Swiss surveillance laws that could mandate mass data collection, policies that are currently outlawed inside the EU. Proton framed the move as building an independent EuroStack to ensure European technological sovereignty.

Why it matters

For regular users, Lumo solves a very real dilemma. You finally have a reliable daily assistant where you can drop NDA documents, sensitive financial records, or private thoughts without worrying about data leaks. The fact that it requires zero sign-up makes it a no-brainer to bookmark for quick sensitive tasks. That said, because Lumo relies on open-source weights hosted on European clusters, its raw reasoning may lag behind the absolute frontier models like GPT-4o or Claude 3.5 Sonnet on complex programming or deep math.

For the AI market, Proton is taking a smart, differentiated lane. While OpenAI, Google, and Apple battle over multi-agent workflows and consumer ecosystem lock-in, Proton is capturing the high-trust niche: lawyers, healthcare workers, journalists, and privacy-conscious enterprises. The challenge will be cost. Running self-hosted European inference without selling user data or ads is brutally expensive, and Proton will have to prove that its Lumo Plus subscriptions can sustain that overhead.