The Lumo Insider’s Guide
Everything we know about Lumo in one document: what it costs, its grades, getting a refund, getting help and what else to look at. Read it here, or keep a copy.
Lumo
The Insider’s Guide
Proton's private AI assistant with zero-access encrypted chats
Every plan, grade, refund rule and rival among AI assistants, read from Lumo’s own pages.
Made by Proton AG · checked Oct 5, 2026 · toolgpa.com
Contents
- 01WelcomeWhat it is, who it suits, its grades and the ten things to know first
- 02What it costsEvery plan, the free plan, ways to pay less and how prices have moved
- 03What it doesIts main features, where it runs, what it works with and who makes it
- 04Where it standsIts grades against its category, and whether to keep it or make your own
- 05The alternativesThe tools it is most often weighed against, side by side
- 06Quick answersThe questions people ask about it, each answered in a line or two
- 07About ToolGPAWho made this guide, what else is on the site, and how to cite it
ToolGPA put this guide together from Lumo’s own pages, its app-store listings and our grades. Every fact in it is on Lumo’s page too, where it is kept up to date. Checked Oct 5, 2026.
Part 01 · Overview
Welcome
What it is, who it suits, its grades and the ten things to know first
2.2
GPA, above 4 of the 57 other AI assistants we grade
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.
To get you started, here are 9 things to know about Lumo, taken from its own pages and our grades.
You can start a chat with no account at all, but the rating is what we go by.
- 1
Best for private AI chat with zero-access encryption
Every limit is vague: Free is "limited" and Plus is "more", with no numbers for either.
- 2
Paid plans start at $9.99 a month
As its pricing page puts it: $9.99 per month, billed yearly ($119.88), or $12.99 billed monthly.
- 3
There is 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.
- 4
It runs on 3 platforms
Web, iOS and Android.
- 5
Zero-access encrypted chats
Conversations are stored with zero-access encryption so that only you can read them; Proton says it cannot access them.
- 6
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.
- 7
Web search
Built-in web search brings real-time information into answers. It is included in the free plan.
- 8
A 2.2 GPA, above 4 of 57
That is against the other AI assistants we grade, on value, the free plan, features, ease of use and platforms.
- 9
Keep it
To replace Lumo you would be making an AI model, which you can rent by the request but not make. That is not a weekend's work, with an AI app builder or without one.
Lumo at a glance
- Pricing
- Free plan, from $9.99 per month, billed yearly ($119.88), or $12.99 billed monthly
- Free plan
- Yes
- Free trial
- None stated
- Runs on
- Web, iOS, Android
- Made by
- Proton AG, since 2025
- Category
- AI Assistants
- Our grade
- 2.2 GPA, fair
- Store rating
- 3.9 on the App Store, 537 ratings
The report card
Best for private AI chat with zero-access encryption
Lumo is Proton's AI assistant, with chats stored under zero-access encryption that Proton says it can't read, and you can try it without an account. Every limit is vague: Free is "limited" and Plus is "more", with no numbers for either. There's no desktop app and no agents, it links only to Proton Drive, and its iPhone app sits at 3.9.
| Subject | Grade | Comment |
|---|---|---|
| Value for money | C | Lumo AI Plus is $9.99 a month billed yearly, which is $119.88 in one go, or $12.99 monthly: the middle of this category. What the extra buys is more of everything, with no numbers from Proton on how much more. |
| Free plan and trial | C | Free needs no Proton account and no card, and web search and small uploads are in it. But Max model use, messages, chat history and image generations are all limited, you get 1 Project, and Proton puts no numbers on any of it. |
| Features | C | Chat, web search, image generation, Projects and files from Proton Drive, all behind zero-access encryption, with the code open source. The basics, and a shorter list than the big assistants': no agents, no desktop app, and Proton Drive is all it links to. |
| Ease of use | C | 3.9 from about 540 App Store ratings, well short of where our B starts. You can start a chat with no account at all, but the rating is what we go by. |
| Platforms and integrations | B | Web, iPhone and Android, so it's on your phone and in any browser. No desktop app is listed, though, and it only connects to Proton Drive, with no API on the listing. |
An A is worth 4 points, a B 3, a C 2, a D 1 and an F nothing. The GPA is the average of the five.
Who Lumo is for
- Fits if you want an assistant whose maker says it can't read your chats or train on them
- Works for people whose files already live in Proton Drive, since you can link them in
Who it is not for
- Tight if you're staying free, with 1 Project, small uploads only, and limits Proton doesn't put numbers on
- Skip it if you want a desktop app, since only web, iPhone and Android are listed
- Not for you if you're buying for a team, as business use is sold separately as Lumo Professional
- Watch out: Plus at $12.99 a month buys "more" of everything, with no numbers on how much more
- Too light for agents or links to other apps: Proton Drive is all it connects to, and there's no API listed
Good to know
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.
Part 02 · Pricing
What it costs
Every plan, the free plan, ways to pay less and how prices have moved
$9.99
A month to start. There is a free plan too
Lumo has a free plan. Paid plans start at $9.99 per month, billed yearly ($119.88), or $12.99 billed monthly.
What the extra buys is more of everything, with no numbers from Proton on how much more.
Free
$0
Limited Max model usage, messages, chat history and image generations, with 1 Project. No credit card required.
Lumo AI Plus
$9.99
per 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.
The 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.
Read from proton.me on Oct 5, 2026.
Ways to pay less
Annual discount
23% 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
What the app costs elsewhere
Each country’s App Store price for “Lumo Plus (1 month)”, against $12.99 in the United States, in dollars at the day’s rate. The four cheapest and the four dearest of 11.
| Country | Price there | In dollars | Against the US |
|---|---|---|---|
| Turkey | ₺329,90 | $6.71 | 48% less |
| Indonesia | Rp 129ribu | $7.21 | 44% less |
| India | ₹ 719 | $7.43 | 43% less |
| Philippines | ₱ 489.00 | $7.78 | 40% less |
| Canada | $16.49 | $11.59 | 11% less |
| United Kingdom | £10.90 | $14.41 | 11% more |
| Germany | 12,99 € | $14.56 | 12% more |
| Australia | $21.49 | $15.00 | 15% more |
Part 03 · Features
What it does
Its main features, where it runs, what it works with and who makes it
3
Places it runs: Web, iOS and Android
Proton's private AI assistant with zero-access encrypted chats. Here is what it does, as its own site describes it, and what it covers: open source, AI features, chat assistant, AI search.
Chat, web search, image generation, Projects and files from Proton Drive, all behind zero-access encryption, with the code open source.
- 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.
Where it runs
- Web
- iOS
- Android
What it works with
- Proton Drive
Lumo is made by Proton AG, and has been around since 2025.
Part 04 · Standing
Where it stands
Its grades against its category, and whether to keep it or make your own
4/57
Other AI assistants it is graded above
Lumo's GPA of 2.2 is higher than 4 of the 57 other AI assistants we grade, and level with 7.
It stands best on platforms and integrations (B, above 23 of 57) and worst on features (C, above 0).
Its paid plans start at $9.99 a month, against a middle price of $10 for the category: 17 of the 38 others that charge start lower.
On features, ease of use and platforms it scores 2.3 out of 4. 14 tools score higher and cost less.
Each grade against the category
Every bar is all 58 AI assistants we grade, cut by the letter each got. Lumo’s own letter is outlined.
- CValue for moneyAbove 5 of 57
- CFree plan and trialAbove 5 of 57
- CFeaturesAbove 0 of 57
- CEase of useAbove 3 of 57
- BPlatforms and integrationsAbove 23 of 57
Price against what you get
Each dot is one of 45 AI assistants. Further left costs less; higher up scores better on features, ease of use and platforms. Lumo is the marked dot.
What paid plans start at, a month (each step along is roughly double) →
Keep it, or make your own?
Whether this is something you could build for yourself with an AI app builder, and what you would give up.
Keep it
To replace Lumo you would be making an AI model, which you can rent by the request but not make. That is not a weekend's work, with an AI app builder or without one.
That makes this kind of software worth paying for, not this one in particular: 46 of the 57 other AI assistants grade higher. It costs $119.88 a year. Lumo is open source, so there is a third way: take its code and run it yourself.
What you could not
- An AI model, which you can rent by the request but not make.
- A search engine with an AI model behind it.
- A real app for iOS and Android. Something home-made would be a web page.
What this rests on. Lumo’s listing: what it does, where it runs, what it plugs into and what it costs. It is a judgement about the kind of software this is. We have not built a replacement for it, and making your own means looking after it too. How we decide, and every tool’s verdict.
Part 05 · Alternatives
The alternatives
The tools it is most often weighed against, side by side
Duck.ai, Venice, Confer, Mistral Vibe and ChatGPT
The 5 tools Lumo is most often weighed against, with where each one differs from it.
- 2.4GPA
Duck.ai
Free plan · from $9.99/mo
Private, anonymized chat with third-party AI models.
- Only Duck.ai lists macOS and Windows apps.
- Lumo is open source, according to its own site.
- Lumo also covers AI search.
- 2.6GPA
Venice
Free plan · from $18/mo
Privacy-focused AI app for chat, images and video across many models.
- Lumo is open source, according to its own site.
- Venice is end-to-end encrypted, according to its own site.
- 2.2GPA
Confer
Free plan · from $34.99
End-to-end encrypted AI assistant from the creator of Signal.
- Only Lumo lists an Android app.
- Lumo is open source, according to its own site.
- Confer is end-to-end encrypted, according to its own site.
- 3.0GPA
Mistral Vibe
Free plan · from $14.99/mo
Mistral's AI chat assistant and coding agent, formerly Le Chat.
- Lumo is open source, according to its own site.
- Mistral Vibe also covers AI agents and research.
- 3.4GPA
ChatGPT
Free plan · from $8/mo
OpenAI's general-purpose AI assistant for chat, images and voice.
- Only ChatGPT lists macOS, Windows and Linux apps.
- Lumo is open source, according to its own site.
Part 06 · Questions
Quick answers
The questions people ask about it, each answered in a line or two
14
Questions, each answered in a line or two
The short version of everything above, for when you only need the answer. Each one is told in full in its part of the guide.
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.
How much does Lumo cost?
Lumo lists 2 plans. Free: $0.
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.
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.
How does Lumo compare with other AI assistants?
Lumo's GPA of 2.2 is higher than 4 of the 57 other AI assistants we grade, and level with 7.
Is Lumo good value for money?
ToolGPA grades Lumo C for value for money. Its paid plans start at $9.99 a month, against a middle price of $10 for the category: 17 of the 38 others that charge start lower.
Could I make my own version of Lumo?
To replace Lumo you would be making an AI model, which you can rent by the request but not make.
Where this guide comes from
The prices, plans, platforms and features were read from Lumo’s own pages on Oct 5, 2026, and the grades were given on Oct 10, 2026. Graded from this listing, whose facts were read from Proton's own pages on 5 October 2026, and its App Store rating. Also tested with a demo account on 2026-02-19.
Every tool we list gets five grades, A to F, each with its reason, and a GPA that averages them. How each is decided is at toolgpa.com/grades. This guide is ToolGPA’s own work; it is not made, paid for or approved by Proton AG. Prices change, so check lumo.proton.me before you buy.
Part 07 · About
About ToolGPA
Who made this guide, what else is on the site, and how to cite it
3,189
Tools graded, in 94 categories
ToolGPA grades software the way a school report grades a pupil: five subjects, a letter for each with the reason written beside it, and a GPA that averages them. Prices, plans and platforms are read from each maker’s own pages and dated, so you always know how fresh a figure is.
Every grade, review and ranking on ToolGPA is our own judgement. No company can pay for a grade or change one. Every tool on the site has a guide like this one, free to download and pass on. It all lives at toolgpa.com.
3,189
tools graded
94
categories
426
price changes on record
579
apps priced in 12 countries
What else is on toolgpa.com
- Lumo, kept up to dateEverything in this guide, with prices and grades as they are todaytoolgpa.com/tools/lumo
- How grades are givenThe rules behind every letter and every GPAtoolgpa.com/grades
- Value chartsWhat each tool costs against what it scores, for every categorytoolgpa.com/charts
- CompareAny two tools side by side, plan by plantoolgpa.com/compare
- Price changesEvery price rise and cut on record, each with its sourcetoolgpa.com/price-changes
- Prices by countryWhat apps cost on the App Store in 12 countriestoolgpa.com/prices-by-country
- Pay lessEvery public discount: yearly billing, students, nonprofitstoolgpa.com/save
- Keep or makeWhich tools are worth paying for, and which you could build yourselftoolgpa.com/keep-or-make
Scan for the live page
Prices and grades as they are today
Quoting this guide?
Please name ToolGPA and link to the live page, so readers can check the figures for themselves:
ToolGPA, "Lumo: The Insider's Guide", checked Oct 5, 2026. https://toolgpa.com/tools/lumo
Know someone choosing between AI assistants?
Send them this guide: toolgpa.com/tools/lumo/guide
ToolGPA elsewhere: youtube.com/@toolgpa
See our other guides
The best-graded AI assistants after Lumo, each with an Insider's Guide of its own.
- AI Assistants Insider's GuideEvery one of the 58 AI assistants we grade, compared
- Gemini Insider's GuideGoogle's AI assistant, tied into Gmail, Docs and other Google apps3.8 GPA
- Chatbox Insider's GuideAI chat client for your own API keys or a hosted model plan3.4 GPA
- ChatGPT Insider's GuideOpenAI's general-purpose AI assistant for chat, images and voice3.4 GPA
Choosing software? Every tool graded, every price dated.
Compare tools at toolgpa.com ›Everything in this guide is ToolGPA’s own summary of what Lumo’s pages, its app-store listings and public reviews said on the dates shown. Grades are our judgement under the rules at toolgpa.com/grades. Every grade, review and ranking on ToolGPA is our own judgement. No company can pay for a grade or change one. Lumo is a trademark of its owner, and this guide is not made, paid for or approved by Proton AG. Prices and plans change: check lumo.proton.me before you buy.