Lumo by Proton

3.9
2.51K reviews
Content rating
Rated for 3+
100K+
Downloads
Content rating
Rated for 3+
Learn more
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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"
Updated on
Jul 3, 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

3.9
2.38K reviews
Ridge
July 4, 2026
Full rewrite cos I really wanna love it. Reminiscent of GPT-4, the info it collates is really good and follows instructions well. But the 7 day chat limit is killing me rn, even having it go into archive mode so I can't respond would be better so I don't lose access to the info. The sandglass icon comes up at like 5 days so I never know when it's actually gonna disappear. Also whilst selecting text, when you need to scroll, it'll select EVERYTHING so it's very hard to copy and paste on mobile.
1 person found this review helpful
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Proton AG
June 25, 2026
Thank you for the review. With the free plan, chats are saved for a maximum of 7 days from the moment they were created. You may consider upgrading to Lumo Plus for extended chat history. On another note, our team is aware of the issue with chats disappearing, and they're working on a fix. Make sure to keep the app up-to-date for any improvements.
AE
July 4, 2026
The application used to work on my Android phone just fine.. but now it keeps showing me a screen saying "introducing Lumo AI version 2.0". And that screen will NOT go away. There's nothing you can do to continue using the application and get rid of that screen. I have no idea what's going on, but I think I might end up uninstalling unfortunately. I would love to post a screenshot of that error message here but I don't see an option to upload a file.
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Proton AG
July 6, 2026
That doesn't sound right. Are you seeing an option to X out of the pop-up? If not, try reinstalling the app from scratch to see how it goes. Should the issue persist, contact us through the contact form on our website with a screenshot of the behavior so we can have a better perspective and assist you further.
Anmol (viola)
June 21, 2026
The best AI you can use right now! The answers are very good, and the little cat searches the whole internet for you! But there's one thing: if you turn on light or dark mode, the app takes a few seconds to switch. I'd suggest the devs add a feature where you can name the cute cat! Overall, I'd say everyone should give this app a try!
5 people found this review helpful
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What’s new

Fixed multiple bugs that were reported by the community. Thank you.