Lumo by Proton

Lumo is a cutting-edge AI assistant developed by Proton, the trusted European company behind encrypted email, VPN, cloud storage, and password management—used by over 100 million people globally. What sets Lumo apart is a simple yet powerful principle: your privacy comes first.

Confidential Conversations, Always

Lumo is built to never log your chats. What you ask stays on your device—Proton cannot see or access it, nor can anyone else. Your conversations won’t be stored, shared, or used to train AI models.

Zero-Access Encryption

Thanks to zero-access encryption, any chat history you choose to save is encrypted and can only be read by you. Even Proton, the app’s creator, has no way to view your conversations.

Open Source Transparency

Lumo is fully open source, unlike many proprietary AI chatbots. Anyone can inspect its code and verify that it respects your privacy, giving you peace of mind that your data isn’t being exploited.

GDPR-Compliant and Based in Europe

As a European service, Lumo operates under strict GDPR regulations and resides outside U.S. jurisdiction. Your personal data is protected by some of the world's strongest privacy laws—and you can delete your data anytime.

No Ads, No Trackers, No Surveillance

Lumo runs on a sustainable, ad-free model and does not sell your information to third parties. Unlike Big Tech AI services, it doesn’t monetize your data or show you ads.

Use Without Signing Up

Get instant access to Lumo without needing to log in or create an account. If you want extended chat history, file uploads, and unlimited chats, upgrading to Lumo Plus unlocks advanced features.

Multilingual Support

Lumo understands and responds in 11 languages, including English, Spanish, French, German, Italian, Portuguese, Dutch, Russian, Chinese, Japanese, and Korean.

Lumo Plans

Free Tier

· Limited usage

· Basic chat history

· Limited chat favorites

· Upload small files

· No login required

Lumo Plus (from €9.99/month)

· Unlimited chats

· Fastest AI responses

· Extended chat history

· Unlimited favorites

· Upload multiple/large files

FAQs

1. What makes Lumo the best private AI chatbot?

Lumo uses zero-access encryption to ensure your chat history is only accessible on your devices. No logs, no data collection—your conversations are private and secure.

2. Can Lumo be used without signing up?

Yes. Lumo is accessible without creating an account, allowing for quick and private chats. However, logging in enables enhanced features like chat history and file uploads.

3. Is my data used to train the AI?

No. Lumo never uses your data to train AI models. What you share in a conversation remains private and is not stored, logged, or analyzed.

4. Which languages does Lumo support?

Lumo currently supports: English, Spanish, French, German, Italian, Portuguese, Dutch, Russian, Chinese, Japanese, and Korean.

5. How is Lumo different from other AI chat assistants?

Lumo is open source, ad-free, and based in Europe, offering true privacy with no logging and full user control—unlike many Big Tech alternatives.

Version History

v0.1.3—17 Sep, 2025

Squished payment screens back into shape - no more getting stuck on tiny screens like a cat in a too-small box

Fixed those pesky GrapheneOS debug errors that were making us hiss and swipe at the screen

Composer now stays put instead of wandering around like a curious kitty - much more stable positioning

Caught and fixed multiple small bugs (literally, we're cats - it's what we do)

v0.1.2—28 Jul, 2025

Minor bug fixes and improvements. Install or update to the newest version to check it out!

v0.1.1—23 Jul, 2025

Minor bug fixes and improvements. Install or update to the newest version to check it out!