Duck.ai vs Lumo
We give Duck.ai a 3.0 GPA and Lumo a 2.8, out of 4.0. Duck.ai grades higher on ease of use. They get the same grade on value for money, the free plan, features and platforms.
Price, platforms and features side by side. The table says where each price was read and when.
Duck.ai
Private, anonymized chat with third-party AI models
Lumo
Proton's private AI assistant with zero-access encrypted chats
How we grade them
| 3.0GPADuck.aiVery good | 2.8GPALumoGood | |
|---|---|---|
| Value for money | BPlus is $9.99 a month or $99.99 a year, about typical, and adds GPT-5.6 Terra, Claude Sonnet 4.6 and higher limits. It comes with DuckDuckGo's VPN and identity services whether you want them or not. The top Claude and GPT models need Pro, at $19.99 a month. | BLumo AI Plus is $9.99 a month billed yearly, which is $119.88 in one go, or $12.99 monthly. About typical for a paid assistant. It buys more of the Max model, messages, history and images, plus unlimited Projects and Custom Lumos, but Proton doesn't say how much more. |
| Free plan and trial | BFree with no account: six chat models, image creation and voice chat, and PDF uploads of up to 15 pages. There's a daily usage limit, though, and the listing can't say how big it is. So no A. | BFree needs no Proton account and no card, and it includes web search and small file uploads. 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 | BChat with models from OpenAI, Anthropic and Mistral AI, make images, talk by voice or dictate, and upload images and PDFs. Solid basics with privacy on top. The gaps: PDFs stop at 15 to 50 pages depending on your plan, and spreadsheets aren't supported. | BChat, web search, image generation, Projects and files pulled in from Proton Drive, all behind zero-access encryption, with the code open source. That's the basics done with care. It's a shorter list than the big assistants', though, and Proton Drive is the only thing it links to. |
| Ease of use | BOpen duck.ai and type. No account, no sign-up, nothing to set up. There's no App Store rating on record for it, since it has no standalone app, so it stops at a B. | C3.9 from about 540 App Store ratings, well short of where our B starts. A pity, because getting going is simple: you can start a chat with no account at all. |
| Platforms and integrations | BAny web browser, plus the DuckDuckGo browser on iPhone, Android, Mac and Windows, where it's built in. There's no standalone app, and nothing on the listing says it connects to other tools or offers an API. | BWeb, 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. |
| Best for | mainstream AI models with no account | private AI chat with zero-access encryption |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: Duck.ai and Lumo. How we grade
Where they differ
- Duck.ai starts at $9.99 per month, or $99.99 per year (DuckDuckGo Plus). Lumo starts at $9.99 per month, billed yearly ($119.88), or $12.99 billed monthly.
- Only Duck.ai lists macOS and Windows apps.
- Lumo is open source, according to its own site.
- Duck.ai also covers dictation.
- Lumo also covers AI search.
At a glance
| Duck.ai | Lumo | |
|---|---|---|
| Pricing | Free plan | Free plan |
| Starts at | $9.99 per month, or $99.99 per year (DuckDuckGo Plus) | $9.99 per month, billed yearly ($119.88), or $12.99 billed monthly |
| Free plan | Free with no account required and a daily usage limit. Free models include Claude 4.5 Haiku, Mistral Small 4, GPT-5.4 nano and mini, gpt-oss-120b and Gemma 4 31B; PDF uploads stop at 15 pages. | 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 | The DuckDuckGo subscription has a free trial at sign-up; the help page does not state its length. | None listed |
| Web | ||
| macOS | ||
| Windows | ||
| iOS | ||
| Android | ||
| Made by | DuckDuckGo | Proton AG |
| Price read from | duckduckgo.com | proton.me |
| Checked | Oct 5, 2026 | Oct 5, 2026 |
Who each one suits
Duck.ai
- People who want to use mainstream AI models without an account
- Privacy-minded users who do not want chats used for model training
- DuckDuckGo browser users who want an assistant built in
Lumo
- 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
Duck.ai
- Free use has a daily limit, and the most advanced Claude and GPT models are reserved for Plus and Pro subscribers.
- Advanced models cannot be bought on their own: the subscription bundles them with DuckDuckGo's VPN and identity services.
- The subscription is sold only to residents of the US, UK, EU and Canada, and its VPN and identity features work only in the DuckDuckGo browser.
- There is no standalone app: outside a web browser, Duck.ai is built into the DuckDuckGo browser for iOS, Android, Mac and Windows.
Lumo
- 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
Duck.ai
- Anonymized chats
- Metadata such as your IP address is removed before a prompt reaches the model provider, so requests appear to come from DuckDuckGo rather than from you.
- Choice of models
- Free models come from Anthropic, Mistral AI and OpenAI, plus two open models hosted by Tinfoil. Subscribers add more advanced Claude and GPT models.
- Chat history kept on your device
- Recent chats are saved locally by default, up to 5 can be pinned, and the Fire Button deletes the rest. Optional Sync & Backup stores chats end-to-end encrypted.
- Image creation
- Select New Image, describe what you want, then refine the result with follow-up prompts. A daily limit applies, with higher limits for subscribers.
- Voice chat and dictation
- Speak with an OpenAI voice model over an encrypted relay, or dictate a prompt for up to 5 minutes per session. Audio is not kept after the session ends.
- Image and PDF uploads
- Some models accept image and PDF uploads, with PDF limits of 15 pages on Free, 35 on Plus and 50 on Pro. Spreadsheets are not supported.
Lumo
- 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.
Plans
Duck.ai
Free$0
Six free chat models, image creation and voice chat within a daily limit, with PDF uploads of up to 15 pages.
Plus$9.99
per month, or $99.99 per year, plus tax if applicable
Adds GPT-5.6 Terra and Claude Sonnet 4.6, higher daily and weekly limits and 35-page PDF uploads, plus DuckDuckGo's VPN and identity services.
Pro$19.99
per month, or $199.99 per year, plus tax if applicable
Everything in Plus, with Claude Opus 4.8 and GPT-5.6 Sol, higher reasoning effort, 2x the Plus usage limits and 50-page PDF uploads.
Lumo
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.
Ways to pay less
Duck.ai
- Annual discount
About 17% off with yearly billing
Plus is $99.99 a year against $9.99 a month, and Pro is $199.99 a year against $19.99 a month, a saving of about 17% over twelve monthly payments.
Lumo
- 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.
