Lumo by Proton

In-app purchases
3.14K reviews
Content rating
PEGI 3
100K+
Downloads
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About this app

"Lumo is a zero-access encrypted AI assistant that keeps every conversation private. Your data is never logged, shared, or used to train models. Your chats are yours, and yours alone.

Built by Proton, the privacy brand trusted by over 100 million people and the team behind Proton Mail, VPN, Drive, and Pass.

THOUGHTFUL HELP FOR ANY TASK
Lumo handles everything from quick questions to more complex work. Choose Fast for quick answers or Thinking for multi-step reasoning.

FAST, POWERFUL WEB SEARCH
Get precise, real-time answers in seconds. Lumo cites live sources so you can verify facts, dig deeper, and stay current on news, events, financial data, and more.

CREATE AND REFINE IMAGES AND FILES
Work with images and documents just by telling Lumo what you need, from generating and editing images to analyzing documents. Connect your Proton Drive account for seamless access to stored files.

AI THAT EVOLVES OVER TIME
Lumo gets better every time you use it. Memory retains context and preferences across sessions, and you can set tones and styles to get the exact Lumo experience you want.

STAY PRODUCTIVE AND ORGANIZED
Projects give you dedicated encrypted spaces for tasks that span multiple chats, files, and instructions, while Custom Lumos let you create assistants tailored for specific tasks. Switch between light and dark modes for a more comfortable experience throughout the day.

GHOST MODE
For conversations where you want maximum privacy, choose Ghost Mode. Chats are instantly deleted once you close them for greater peace of mind.

PRIVACY YOU CAN VERIFY
Lumo is founded on zero-access encryption with no server-side chat logs, and never uses your data for profit or model training. Like all Proton products, Lumo is built and hosted in Europe and is fully open-source.

Lumo helps you stay productive, curious, and informed — without ever compromising your privacy. Start a confidential chat for free today.

For more information, visit our website: https://lumo.proton.me/about
Terms of service: https://lumo.proton.me/legal/terms
Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Our open-source code base: https://github.com/ProtonLumo/ios-lumo"
A private AI assistant by Proton
Updated on
Oct 1, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • No data shared with third parties
    Learn more about how developers declare sharing
  • This app may collect these data types
    Personal info, App activity, and App info and performance
  • Data is encrypted in transit
  • You can request that data be deleted

Ratings and reviews

2.96K reviews
Lee Forest
September 16, 2026
Great all around AI. Doesn't do videos. But handles images, coding, research, writing, brainstorming, planning, conversation, whatever else you might expect from the typical AI. It's been my goto for most of my tasks and I'm not disappointed. Startup can be a little slow but given the privacy aspect and all it offers I can deal with that.
5 people found this review helpful
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Skibidi toilet fan 536
July 9, 2026
I like it? I enjoyed using it, and it not selling my data is a great boon. So far, I only have just a few complaints: It seems to be having some lag spikes during reasoning and startup. Having the chats auto deleted without an active subscription and a way to export them isn't very nice either. An export/import feature would be nice for chats. Some use cases would benefit nicely.
16 people found this review helpful
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Proton AG
July 9, 2026
Thank you for the review. We're aware of the issues you've mentioned, and our team is working on fixing them. Make sure to keep the app up-to-date for any improvements. Meanwhile, we've documented all your feedback accordingly.
Ronny Astrada
September 5, 2026
It's like a non-functional AI. Even bringing up the sending button made the app crashes! 😭 I'm waiting for your improvement though. How much time should I wait? 3 months? Edit: turns out just need to delete both cache and user data and starting anew. Problem fixed. Although not as fast as Gemini, but it can help me with DCF analysis fine!
5 people found this review helpful
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Proton AG
August 24, 2026
That doesn't sound right. Could you share more details about the issue? Are you receiving any error messages? What are the specific steps you're taking that trigger the crash? Where exactly did you download the app from? Contact us through the contact form on our website with more details so we can investigate further and help you troubleshoot.

What’s new

Lumo now lands on its feet when you sign in, with a fix for a crash some of you hit when logging into your account. 😺