Proton releases version 2.0 of privacy-focused AI chatbot Lumo

Proton, the Swiss tech company behind privacy services such as ProtonMail and ProtonVPN, released version 2.0 of its AI chatbot Lumo on 30 June 2026. The update introduces two new model variants, Lumo 2.0 Lite and Lumo 2.0 Max, which score 127 percent and 240 percent higher respectively than the previous version 1.4 on the Artificial Analysis Intelligence Index benchmark.

Lumo is an open-source AI chatbot that provides users with AI assistance while their conversations are not stored or used for model training. The service runs entirely on Proton's own infrastructure in data centres in Switzerland, Germany and Norway, and therefore falls under Swiss privacy law. Not even Proton itself can see what users discuss on Lumo.

Since its initial launch on 23 July 2025, more than ten million people have used the chatbot. In the run-up to version 2.0, Proton also released interim updates on 21 August and 16 October 2025, and on 30 October 2025 launched a business subscription called Lumo for Business.

How Proton structures its privacy model

Proton was founded in 2014 by Andy Yen, Jason Stockman and Wei Sun, three researchers who met at CERN. The company is headquartered in Plan-les-Ouates, near Geneva, and now has around 500 employees across offices in Vilnius, Taipei, Skopje and Zurich.

Proton operates without venture capital investors. Its services are funded through paid subscriptions; its first product, ProtonMail, was made possible back in 2014 by a crowdfunding campaign that raised more than 500,000 dollars from over ten thousand individuals. In June 2024, Proton AG transferred majority ownership to the Proton Foundation, a non-profit organisation. That structure is partly designed to prevent the company from ever being acquired by an external party with different priorities. Tim Berners-Lee, the inventor of the World Wide Web, has been a member of the foundation's supervisory board since June 2024.

Proton had more than one hundred million registered accounts across all its services in 2024. Lumo therefore benefits from an existing user base that most new AI startups do not have.

What Lumo 2.0 offers and what it costs

Lumo 2.0 comes in two variants. The Lite variant targets everyday tasks and is aimed at users looking for a fast, privacy-friendly alternative to mainstream chatbots. The Max variant is more powerful and targets more complex tasks, comparable in capability to Claude Sonnet and ChatGPT, according to Proton. The benchmark scores support that ambition: the Max variant scores 240 percent higher than version 1.4 on the Artificial Analysis Intelligence Index.

Lumo is available for free in a basic variant. A Lumo Plus subscription costs 9.99 dollars per month and provides access to higher usage limits. Business users can opt for Lumo Professional, with subscriptions starting at 11.99 dollars per month. The Lumo for Business plan, aimed at teams and organisations, launched in late October 2025.

The chatbot is open-source, meaning its source code is publicly accessible and can be audited by third parties. For privacy-conscious users and organisations, this is a relevant feature, as they do not have to rely solely on the provider's own claims.

European context and what this means for the AI market

Lumo explicitly positions itself as a European alternative to American AI services such as ChatGPT and Google Gemini. While those services process data on servers under US jurisdiction, Lumo processes all data on European and Swiss servers, beyond the reach of the US Cloud Act.

For European policymakers and regulators determining how AI services can comply with the GDPR and the AI Act, Proton's approach offers a concrete example of how privacy safeguards can be technically embedded in an AI service, rather than being added after the fact through policy documents. The combination of an open-source model, European infrastructure and a non-profit structure distinguishes Lumo from most competitors in this space.

For founders and investors in the European AI scene, Proton demonstrates that there is a market for AI services that treat privacy as a core product. With more than ten million users in less than a year, demand is clearly present, although the question remains how effectively Lumo can compete in the long term against the considerably larger budgets and model capabilities of American tech giants.