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About
Proton Lumo is an AI assistant designed from the ground up to respect user privacy. Built by the scientists behind Proton Mail, Proton VPN, and the nonprofit Proton Foundation, Lumo delivers AI chat capabilities without the data harvesting practices common among Big Tech AI products. Unlike competitors, Lumo keeps no logs of your queries or responses, applies zero-access encryption so saved conversations can only be read on your device, and refuses to use your data for model training. The codebase is fully open source, allowing anyone to independently verify its privacy claims. As a European service headquartered outside US jurisdiction and subject to GDPR, Lumo cannot share your information with advertisers, governments, or any third parties — and users can delete their data at any time. The free tier allows basic access, while Lumo Plus (a paid subscription) unlocks unlimited chats, extended chat history, unlimited favorites, project organization, and the ability to upload multiple or large files. Lumo is ideal for privacy-conscious individuals, professionals handling sensitive information, businesses seeking GDPR-compliant AI tooling, and anyone who wants the productivity benefits of AI without sacrificing personal data.
Key Features
- No-Logs Policy: Proton keeps zero logs of your questions or Lumo's responses, ensuring your AI conversations leave no traceable footprint.
- Zero-Access Encryption: Saved conversations are encrypted so only you can decode them on your device — not even Proton can read them.
- Fully Open Source Code: Lumo's codebase is publicly available, allowing anyone to independently verify its privacy and security guarantees.
- GDPR-Compliant European Service: Based in Europe and subject to GDPR, Lumo cannot share your data with advertisers or governments, and you can delete your data at any time.
- No AI Training on Your Data: Unlike most AI assistants, Lumo never uses your conversations to train or improve its models, keeping your data exclusively yours.
Use Cases
- Privacy-conscious individuals who want AI assistance without their queries being logged, profiled, or used for advertising.
- Business professionals and teams handling sensitive information who need a GDPR-compliant AI chat tool.
- Developers and security researchers who want to audit an AI assistant's code and privacy claims independently.
- European users or companies requiring AI tooling that operates strictly within EU privacy regulations.
- Existing Proton ecosystem users (ProtonMail, Proton VPN, Proton Drive) looking to extend their private workflow with AI assistance.
Pros
- Industry-Leading Privacy Guarantees: Combines no-logs policy, zero-access encryption, open-source transparency, and GDPR compliance — a privacy stack unmatched by any major AI assistant.
- Trusted Proton Ecosystem: Built by the proven team behind ProtonMail and Proton VPN, Lumo benefits from years of credibility in privacy-first technology.
- Open Source Transparency: The fully public codebase allows security researchers and users to verify claims independently rather than relying on promises.
- Free Tier Available: Users can start chatting with Lumo at no cost, making private AI accessible without an upfront financial commitment.
Cons
- Limited Free Tier: The free plan caps the number of questions and chat history retention, requiring a Lumo Plus upgrade for unrestricted use.
- Newer and Less Feature-Rich Than Rivals: As a newer entrant, Lumo may offer fewer integrations, plugins, and advanced capabilities compared to ChatGPT, Gemini, or Copilot.
- Paid Subscription for Full Value: Key productivity features like unlimited chats, large file uploads, and project organization require a paid Lumo Plus subscription.
Frequently Asked Questions
How does Lumo protect my privacy?
Lumo uses a combination of a strict no-logs policy, zero-access encryption for saved chats, and a commitment to never use your data to train AI models. It is also open source so anyone can verify these claims, and as a European service it is subject to GDPR.
Is Lumo free to use?
Yes, Lumo has a free tier that allows basic AI chat access. For unlimited chats, extended history, project organization, and large file uploads, you can upgrade to Lumo Plus with a monthly or yearly subscription.
Can Proton read my Lumo conversations?
No. Thanks to zero-access encryption, saved conversations can only be decoded on your own device. Proton itself cannot read your chats, and neither can any third party.
Is Lumo's code really open source?
Yes, Lumo's code is fully open source and publicly available for review. This allows developers, security researchers, and users to independently verify its privacy and security architecture.
How does Lumo compare to ChatGPT or Gemini?
Unlike ChatGPT or Gemini, Lumo does not log your chats, does not use your data to train AI models, does not share data with advertisers or governments, has no ad-based business model, and operates under European privacy law. The trade-off is that it may have fewer features and integrations than those more established platforms.
