Lumo
Proton's privacy-first AI assistant, the official said that conversations use zero-access encryption and no data is used to train the model. The code is fully open-source, the service is in Europe and complies with GDPR, and it can be used on the web, iOS and Android.
Updated: 2026-10-26
What is Lumo?
Lumo is an AI assistant launched by Proton. The official website title directly states "Lumo: Privacy-first AI assistant where chats stay confidential". Its positioning on the homepage is "The confidential AI chat assistant", with the subheading "AI should empower you, not exploit you for your data". The meta description provides the technical specification: Lumo is Proton's zero-access encrypted AI assistant that does not track or record your conversations.
Its privacy policy is very specific: the official website states that all conversations are stored with zero-access encryption, and no one (including Proton itself) can access them; it will not and cannot share your information with anyone, including advertisers and governments; Lumo is a European service that complies with GDPR, and you can delete your account at any time. The official website also emphasizes that its code is fully open source and states that it never uses your data to train AI models.
Who is it for?
- Professionals handling sensitive content such as customer privacy data, medical information, and legal materials, with zero-access encryption as its core selling point.
- People who explicitly do not want their data used for advertising targeting and user profiling, with the comparison table on the official website listing "cannot share your data with anyone" as a differentiating feature.
- Technical users who want to verify privacy commitments on their own: the official website provides a security model explanation page and an open-source code repository link.
- Users already using the Proton ecosystem (Mail, VPN, Drive, Pass) have low onboarding costs.
Key features
6Zero-access encrypted conversations
The official website states that all conversations with Lumo are stored with zero-access encryption, readable only by yourself and inaccessible to Proton.
No data used for model training
The official website clearly states "Never uses your data to train AI".
Fully open-source
The official states that the code is fully open-source, allowing anyone to verify its privacy and security implementation, and it provides security model explanations and code access portals.
Data not accessed by third parties
The official website states that it will not and cannot share your information with anyone, including advertisers and governments.
EU Compliance
It is officially stated as a European service located in a high-privacy jurisdiction, compliant with GDPR, and you can delete your account at any time.
Cross-platform & Image Generation
The official website provides download links for Web app, iOS, and Android. Besides Security and Personalization, the Features section also lists Image generation.
How to use Lumo
- The official website has created a comparison table with Gemini, Copilot, OpenAI, and Claude, itemizing whether they use your data for training.
- This is a marketing stance table, and the actual terms shall be subject to the official privacy policy.
- Structured data shows the price field is 0 and marked as free to access.
- For the existence of paid tiers and their prices, please refer to the official website's pricing page.
- The input box on the homepage has a prompt limiting "Max 1,800 characters".
- split long documents into segments first before processing.
- "Not using your data for training" does not mean "sending nothing externally".
- Your actual responses still need to be sent to the model inference service.
- It is recommended to confirm the boundaries by referring to the official security model page.
Traffic & popularity
Data month Sep 2026
Lumo receives about 895.5K visits per month.
Monthly visits
12 monthsTraffic sources
- Direct60.9%
- Search14.4%
- Referrals12.2%
- Mail7.6%
- Social3.9%
- Other1.0%
Top countries
- United States31.1%
- Germany14.2%
- France8.7%
- Switzerland6.6%
- Canada4.2%
Estimated from third-party traffic data.
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