What’s another AI chatbot in an already crowded field? That’s the question Proton is trying to answer today with the release of its new Lumo assistant. And like with its best known service, Proton Mail, the company says Lumo is for those who want a private alternative to what big tech is offering.

Proton says every conversation with Lumo is secured with zero-access encryption, meaning only your device can unlock your content. In the context of an AI chatbot, that has several implications. Most notably, it means not even Proton can view your chats. As a result, the company can’t share your data with governments, advertisers or, for that matter, any other company, and it can’t use your data to train future AI models. “By using Lumo, you can enjoy the benefits of an advanced AI assistant without the risk of your data being misused,” says Proton.

I briefly tried Lumo. It’s a bit slow to generate a response, but you can broadly expect a similar experience to what you would find using ChatGPT or Claude for free. Lumo can search the web to answer questions beyond its knowledge cut-off date, but by default that feature is turned off to further protect user privacy. You can also upload files to Lumo. Here again Proton says the chatbot won’t save any information.

Proton isn’t touting the performance of Lumo’s large language models, but if you’re curious about this sort of thing, it’s powered by a handful of open-source systems, including Mistral NeMo and Mistral Small 3, among others. Proton told The Verge Lumo will filter requests through the model best suited for the task. For example, it will use NVIDIA’s OpenHands system for coding requests.

Lumo is free to use, with a weekly query limit. You don’t need a Proton account to begin a conversation with the chatbot. In addition to being available on the web, Proton offers both Android and iOS apps. A $13 per month Plus plan offers unlimited usage, alongside perks like larger uploads, access to more advanced AI models, priority support and more.

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