About Lumo
Lumo ranks #2 of 9 in AI Chatbots & Companions, holds a 4.4/5 editor rating, starts at Free.
Lumo is Proton’s privacy-first AI assistant for writing, research, coding, file analysis, and image generation. It stands out with a no-logs policy, zero-access encrypted saved chats, open-source models, and a free guest mode.
Best for: Privacy-conscious individuals, researchers, writers, developers, and teams handling sensitive documents.
“A compelling choice for privacy-sensitive users who want a general-purpose AI assistant without chat logs, ad targeting, or model training on their conversations.”
What is Lumo?
Lumo is Proton’s answer to the everyday AI assistant: a chat workspace for questions, writing, brainstorming, coding, translation, document analysis, and image creation. Its defining advantage is privacy. Proton says Lumo does not keep logs of chats, does not use conversations to train its models, and does not share user data with advertisers or other third parties.
For signed-in users, saved conversations, Projects, uploaded files, and memories are protected with zero-access encryption. Lumo also offers optional web search for more current answers, support for large documents and Proton Drive files, and two model choices—Lumo 2.0 Lite and Lumo 2.0 Max—with Fast and Thinking reasoning modes.
The free experience is useful for trying the product and handling lighter workloads. Lumo Plus is aimed at people who want higher limits, faster responses, more Max usage, more image generations, unlimited Projects, and unlimited Custom Lumos.
The trade-off is that Lumo is less broadly integrated into third-party workflows than some mainstream assistants, and its most useful privacy features require a Proton account. As with any generative AI tool, important factual, legal, financial, or health-related outputs should be independently checked.
Pros
- No-logs policy and no training on conversations
- Zero-access encrypted saved chats, Projects, and Memory
- Optional privacy-focused web search
- Supports files, long documents, image generation, and image editing
- Guest access is available without creating an account
Cons
- Higher limits and premium features require Lumo Plus
- Smaller integration ecosystem than ChatGPT, Claude, or Gemini
- Important outputs still need fact-checking
- Some privacy features require signing in to a Proton account
How to Use Lumo
- 1Open Lumo
Go to lumo.proton.me and start a chat as a guest, or sign in with a Proton account for saved history and additional features.
- 2Choose a model and mode
Use Lumo 2.0 Lite for everyday tasks or Lumo 2.0 Max for more demanding work, then choose Fast or Thinking reasoning.
- 3Ask, upload, or search
Enter a prompt, upload a document or image, connect relevant Proton Drive files, or enable web search when you need current information.
- 4Organize ongoing work
Create a Project for a recurring task, add files and instructions, and use Memory when you want personalized responses across sessions.
- 5Verify important answers
Review citations and independently check high-stakes claims before acting on them.
Key Features of Lumo
Core assistant
1General-purpose chat for questions, writing, brainstorming, coding, translation, and planning.
Privacy
2Proton says it does not retain chat logs or use conversations to train its models.
Saved chats, Projects, files, and Memory are encrypted so Proton cannot read them.
Research
1Optional web search adds more current information to responses.
Organization
1Dedicated encrypted workspaces for chats, files, and custom instructions.
Multimodal
2Upload documents, spreadsheets, notes, and images for analysis and summaries.
Create, analyze, and modify images from natural-language instructions.
Personalization
1Personalize responses with saved preferences and purpose-built assistants.
Technology
1Powered by open-source models optimized by Proton and run on infrastructure Proton controls.
Use Cases
- Answer questions and explain complex topics
- Draft, rewrite, translate, and summarize text
- Research current information with optional web search
- Analyze sensitive documents, spreadsheets, and images
- Create and edit images from natural-language prompts
- Debug code and solve technical or mathematical problems
- Organize recurring work in encrypted Projects
Integrations
- Cloud storage
- Proton Drive
- Research
- Web search
Limitations
The strongest saved-chat, Projects, Memory, and higher-usage features require a Proton account or Lumo Plus. Lumo has fewer third-party integrations than the largest AI platforms, and outputs still require verification.