Lumo
Proton's private AI assistant with zero-access encrypted chats
What is Lumo?
Lumo is Proton's AI assistant, built around keeping conversations private: chats are stored with zero-access encryption that Proton says it cannot read, and they are not used to train models. It answers questions, searches the web, generates images and works with files linked from Proton Drive, and its code is open source. The free plan can be used without an account, with Lumo AI Plus above it.
Lumo has a free plan. Paid plans start at $9.99 per month, billed yearly ($119.88), or $12.99 billed monthly. See every plan
Good for
- People who want an assistant that cannot read or reuse their chats
- Proton users who already keep files in Proton Drive
- Trying a private assistant without creating an account
Worth knowing
- The free plan limits Max model usage, messages, chat history, image generations and uploads, and allows 1 Project; Proton gives no exact numbers.
- The download menu lists iOS and Android apps and a web app; no desktop app is listed.
- Business use is sold separately, as Lumo Professional or as part of Proton Workspace.
Key features
- Zero-access encrypted chats
- Conversations are stored with zero-access encryption so that only you can read them; Proton says it cannot access them.
- No training on your chats
- Proton states that conversations are never used to train AI models, to target ads or to build a personal profile.
- Web search
- Built-in web search brings real-time information into answers. It is included in the free plan.
- Files and Proton Drive
- Link files and folders from Proton Drive to give Lumo context. The free plan uploads individual small files; Plus allows multiple large files.
- Image generation
- Turns a description into an image and lets you refine it through follow-up prompts.
- Open-source code
- Lumo's code is published as open source, which Proton says lets anyone verify that it is private and secure.
Lumo pricing
- Starts at
- $9.99 per month, billed yearly ($119.88), or $12.99 billed monthly
- Free plan
- Free plan, usable without a Proton account: limited Max model usage, messages, chat history and image generations, 1 Project, web search and uploads of individual small files.
- Free trial
- None listed
| Plan | Price | What you get |
|---|---|---|
| Free | $0 | Limited Max model usage, messages, chat history and image generations, with 1 Project. No credit card required. |
| Lumo AI Plus | $9.99per month, billed yearly ($119.88); $12.99 billed monthly | More Max model usage, messages, chat history and image generations, unlimited Projects and Custom Lumos, with a 30-day money-back guarantee. |
Read from proton.me on Oct 5, 2026. Prices change, so confirm with Lumo before you buy.
Ways to pay less
- Annual discount23% off with yearly billing
Proton's pricing page lists Lumo AI Plus at $9.99 a month when billed yearly ($119.88 every 12 months) against $12.99 billed monthly, labeled as 23% off.
Stated on proton.me
How people rate the Lumo app
3.9
out of 5 for the iPhone and iPad app
- 5 stars54%
- 4 stars14%
- 3 stars11%
- 2 stars9%
- 1 star13%
537 ratings on the App Store in the United States, read Oct 5, 2026. It rates the app, not everything the product does. See the listing
Works with
- Proton Drive
Lumo alternatives
- Lumo vs Duck.ai
Free plan · from $9.99/mo
- Lumo vs Venice
Free plan · from $18/mo
- Lumo vs Confer
Free plan · from $34.99
- Lumo vs Mistral Vibe
Free plan · from $14.99/mo
- Lumo vs ChatGPT
Free plan · from $8/mo
Common questions
Is Lumo free?
Lumo has a free plan. Free plan, usable without a Proton account: limited Max model usage, messages, chat history and image generations, 1 Project, web search and uploads of individual small files. Paid plans start at $9.99 per month, billed yearly ($119.88), or $12.99 billed monthly.
How much does Lumo cost?
Lumo lists 2 plans. Free: $0. Lumo AI Plus: $9.99 per month, billed yearly ($119.88); $12.99 billed monthly. Prices were read from proton.me on Oct 5, 2026.
What platforms does Lumo work on?
Lumo is available on Web, iOS and Android.
Does Lumo offer any discounts?
Lumo publicly lists the following: 23% off with yearly billing.
How is Lumo rated?
Lumo's iPhone and iPad app averages 3.9 out of 5 from 537 ratings on the App Store in the United States, as read on Oct 5, 2026. That is the store's rating of the app, not a score from us.
Does Lumo have a Windows app?
No Windows app was listed when its pages were read on Oct 5, 2026. Lumo is listed for Web, iOS and Android.
Does Lumo have a macOS app?
No macOS app was listed when its pages were read on Oct 5, 2026. Lumo is listed for Web, iOS and Android.
Is Lumo open source?
Yes. Lumo is open source, according to its own site.
What does Lumo integrate with?
Lumo's listing names Proton Drive. A listing names up to eight integrations, so it may connect to more.
Who makes Lumo?
Lumo is made by Proton AG. It dates from 2025.
What are the alternatives to Lumo?
The closest alternatives to Lumo in our directory are Duck.ai, Venice, Confer, Mistral Vibe and ChatGPT. Each one has a side-by-side comparison with Lumo.
Sources for this page
The prices, plans, platforms and features above were read from these pages on Oct 5, 2026. What people say is linked where it appears.