Updated on September 12, 2026
Lumo 2.0 is the private AI assistant from Proton, the Swiss company behind Proton Mail and Proton VPN, engineered so that nobody can read your conversations, Proton included. It shipped on June 30, 2026, and you can try it for free with no account and no credit card. Lumo Plus costs €12.99 a month, dropping to €9.99 on the annual plan, with the same figures shown in dollars for US customers.
Proton is technically unable to read what you type into Lumo. Conversations are protected by zero-access encryption, a close relative of end-to-end encryption, and only get decrypted on your own device. No logs are kept, and nothing you write is fed back into model training.
Everything runs on servers located in Europe, under Swiss law and outside US jurisdiction. You paste a contract, ask for a summary, and that exchange stays as silent as a Swiss vault. For an extra layer of caution, ghost mode opens a conversation that vanishes the moment you close it.
| Guarantee | What it means for you |
|---|---|
| Zero-access encryption | Proton itself cannot reread your conversations |
| No logs kept | Your questions leave no exploitable trace |
| No training on your chats | Your words never end up inside a future model |
| European servers, Swiss law | Your data sits outside US jurisdiction |
| Ghost mode | The conversation disappears as soon as you close it |
On the Artificial Analysis index, Lumo 2.0 Max scores 240% higher than Lumo 1.4, the Lite model gains 127%, and everyday answers arrive noticeably faster. Proton even claims that for many tasks its testers can no longer tell Max apart from the latest OpenAI and Anthropic models. Under the hood, the assistant runs solely on open large language models, currently Qwen 3.5 and GLM 5.2.
The overhaul goes well beyond the engine. Among the additions in this second generation,
Lumo's free tier starts without an account or a credit card. It includes limited access to the Max model, capped messages, history and images, and a single project (guest mode is also handy on a shared computer, since nothing gets synced there).
Lumo Plus, at €12.99 a month or €9.99 billed yearly, brings more Max usage, more messages, and unlimited projects and Custom Lumos. Teams go through Lumo Professional from €14.99 per seat per month. Proton tweaks these figures from time to time, so treat the official pricing page as the final word.
Around it, Mistral AI plays the French card with Le Chat, DuckDuckGo AI Chat and Brave Leo bet on lightweight anonymity, and Jan keeps everything local. Lumo is the only one of the bunch combining zero-access encryption, images, projects and memory in a single free assistant.
Yes, Lumo can be tried for free without an account or a credit card. The free tier caps Max model usage, messages, chat history, generated images, and allows a single project. Lumo Plus, at €12.99 a month, lifts those ceilings with unlimited conversations, projects and Custom Lumos.
About as private as an online service can get. Conversations are encrypted with zero access, Proton keeps no logs and trains no models on your chats, and everything runs on European servers under Swiss law. The client apps are published under a free software license, so third parties can audit those guarantees.
For everyday tasks, the gap has become hard to perceive according to Proton's own testing, which pits Lumo 2.0 Max against the latest OpenAI and Anthropic models. Independent reviewers add nuance, since ChatGPT keeps an edge on hard coding and long reasoning. In return, none of your questions leave Europe or feed any training set.
Lumo Plus is sold first and foremost as a standalone subscription, at €12.99 a month or €9.99 billed yearly, and Proton regularly changes what its bundles include, so the safest move is to check from your Proton account whether your current plan already unlocks the Plus features. Teams go through Lumo Professional, priced per seat and available inside Proton Workspace, the company's business suite.
Verdict: Private AI has gone mainstream, and Lumo 2.0 proves it with a free tier that makes no compromise on encryption. Lawyers, journalists, HR teams and anyone careful online get, with Lumo 2.0, a free assistant for the things they would never type anywhere else.
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