Lumo
Proton AG
An AI assistant that keeps your chats private and out of training
Lumo costs €9.99/mo for the Lumo AI Plus (annual) plan. There is also a free version.
Price
From €9.99/mo · Free version available
Last checked
September 2026
Best for
Private everyday AI chats
Category
Private AI and encrypted apps
About Lumo
Lumo is the AI assistant from Proton AG, built around what it leaves alone. Your chats do not train its models, your messages are not profiled for ads, and saved conversations are encrypted so that only you can read them. That suits anyone who wants to paste in a client email or a health question without feeding a training set. Proton says the models run on servers it controls in Europe and nothing goes to third parties. The catch: Proton does not say how long chat history is kept, and the free plan limits messages, history and image generation. Anonymized feedback you choose to send on Apertus answers is the one exception to the no-training rule.
Lumo pricing
On the Lumo AI Plus (annual) plan, Lumo costs €9.99 a month or €119.88 a year. A free version exists too. Lumo AI Plus (monthly), the highest plan listed here, comes to €155.88 a year. Read on the provider’s pricing page on September 22, 2026; a monthly subscription can cost more than the yearly rate.
Each plan as the provider lists it, in the currency it showed us, with the date we read it.
Free
- Limited use of the Max model
- Limited messages and chat history
- Limited image generations
- 1 project
- No credit card required
Lumo AI Plus (monthly)
- Billed monthly
- No training on your chats
- Zero-access encrypted chats
- No tracking or profiling
Lumo AI Plus (annual)
- Billed annually
- No training on your chats
- Zero-access encrypted chats
- No tracking or profiling
“A sound first choice for anyone who wants AI help without handing over their conversations. The privacy terms are clear and strict: no training on chats, zero-access encryption, no ad profiling. It loses points because Proton publishes no retention period for chat history, and the free tier caps messages and history.”Editorial team, via AISafeCheck
Where to get it
From €9.99/mo
You sign up and pay on the provider’s own site.
Prices last checked on
Where we earn from a click, it says so under the button.
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Questions about Lumo
More private AI assistants and encrypted apps
View allFrequently asked questions
Does Lumo use my chats to train AI?
No. Proton states that Lumo does not use your conversations to train its models; its privacy page mentions no separate setting for this. The only exception is anonymized feedback you explicitly submit on answers from the Apertus model. Your messages are also not tracked, profiled or used for targeted ads.
Can Proton read my Lumo conversations?
No. Lumo uses zero-access encryption for chats, so only you can read your stored conversations and Proton itself has no access. Proton also says the models run on servers it controls in Europe and that your data is never sent to third parties. What Proton does not publish is how long chat history is kept.
Is Lumo free to use?
Yes, the Free plan needs no credit card. It comes with limited use of the Max model, limited messages and chat history, limited image generations and one project. Lumo AI Plus is the paid plan, billed monthly or yearly, and the price table on this page shows both amounts.
Where we earn from a click, it says so under the button. Prices are what the provider showed on its own pricing page on the date given; its checkout has the final word, including tax.