# Lumo

> Privacy-first AI assistant from Proton with zero-access encrypted chats and no logging

- Category: [AI Assistants](https://finderatlas.com/categories/ai-assistants)
- Pricing: Freemium
- Website: https://lumo.proton.me
- Platforms: Web, iOS, Android
- Mobile app: available
- Made by: Proton AG, founded 2014, Geneva, Switzerland
- Last updated: 2026-10-19
- FinderAtlas page: https://finderatlas.com/tools/lumo

## Overview

Lumo is an AI assistant built by Proton, the Swiss company behind Proton Mail, Proton VPN and Proton Drive. It handles everyday assistant tasks such as answering questions, searching the web, analyzing uploaded files and images, generating images, and drafting or reviewing text and code. Proton positions it as a privacy-focused alternative to mainstream chatbots: conversations are protected with zero-access encryption, Proton says it keeps no logs of prompts or replies, and it says user data is never used to train models. The service is free to try as a guest, and a paid Plus plan raises usage limits.

## Key features

- Zero-Access Encrypted Chats
- Open-Source Models
- Web Search
- Image Generation and Editing
- Projects
- Custom Lumos
- Proton Drive Integration
- Guest Mode
- Memory and Personalization

## Pricing

- **Lumo Free** ($0): Limited free access, no credit card required
- **Lumo Plus** ($12.99/month): Individuals who want higher limits

## Best for

- Everyday AI chat, web-assisted questions, document and image work without conversation logging or training on user data

## Who uses it

- Privacy-conscious individuals
- Existing Proton users
- Journalists and researchers
- Small teams handling sensitive information

## Strengths

- Zero-access encryption on saved chats, with a stated no-logging policy.
- Open-source code and open-source models that can be inspected.
- Permanent free tier with guest access and no credit card.
- Web, iOS and Android apps.
- Run by Proton AG, a Swiss company, and stated to comply with GDPR.

## Limitations

- Free chat history is kept for only 7 days.
- Uses open-source models rather than the proprietary frontier models of larger rivals.
- No desktop app or public API found.
- Lumo Plus limits are described only as "more" than Free, not as numbers, and the plan costs $12.99/month ($9.99/month billed annually).

## Not recommended for

- Users who need the largest frontier models, a public developer API, a desktop app

## Integrations

- Proton Drive

## FinderAtlas editorial scores (out of 10)

- Ease of Use: 8.5/10
- Feature Depth: 7/10
- Value for Money: 7.5/10
- Performance & Speed: 7.2/10
- Documentation & Support: 7.8/10

## Alternatives

- [Duck.ai](https://finderatlas.com/tools/duck-ai): Chat with ChatGPT, Claude and other AI models without handing over your data ([compare](https://finderatlas.com/compare/duck-ai-vs-lumo))
- [DeepSeek](https://finderatlas.com/tools/deepseek): Free AI chat app and low-cost API running DeepSeek's open-weights V4 models ([compare](https://finderatlas.com/compare/deepseek-vs-lumo))
- [Claude](https://finderatlas.com/tools/claude): Anthropic's AI assistant for writing, analysis, coding and working with files ([compare](https://finderatlas.com/compare/claude-vs-lumo))
- [Qwen](https://finderatlas.com/tools/qwen): Alibaba's free AI assistant and open-weight model family, on web, mobile and API ([compare](https://finderatlas.com/compare/lumo-vs-qwen))
- [Mistral Vibe (formerly Le Chat)](https://finderatlas.com/tools/mistral-le-chat): Mistral AI's chat assistant and coding agent for everyday work and software tasks ([compare](https://finderatlas.com/compare/lumo-vs-mistral-le-chat))
- [Grok](https://finderatlas.com/tools/grok): xAI's AI assistant with live X and web search, image and voice tools ([compare](https://finderatlas.com/compare/grok-vs-lumo))
- [ChatGPT](https://finderatlas.com/tools/chatgpt): OpenAI's AI assistant for writing, research, coding, image generation and voice chat ([compare](https://finderatlas.com/compare/chatgpt-vs-lumo))
- [Msty](https://finderatlas.com/tools/msty): Private AI workspace for chatting with local and online models, with your data under your control ([compare](https://finderatlas.com/compare/lumo-vs-msty))

## Recent updates

- 2026-06-01: Added Fast and Thinking modes, image generation and recognition, stronger web search, memory, a larger context window...

## FAQ

**Is Lumo free?**

Yes. Lumo Free has limited model usage, messages, chat history and image generations, plus one Project, and needs no credit card. Lumo Plus is a paid upgrade.

**Does Lumo use my chats to train AI models?**

Proton says it never uses user data to train models and keeps no logs of prompts or replies. The exception noted on its privacy page is anonymized feedback on Apertus 1.5 responses, which users must choose to submit.

**Which AI models does Lumo use?**

Open-source models optimized by Proton. Its privacy page lists Qwen 3.5, GLM 5.3, Image-Turbo, FireRed-Image-Edit-1.1 and Apertus 1.5. They run on servers Proton controls.

**Do I need a Proton account?**

No for limited guest access. A Proton Account is needed to save chat history across devices and to use Projects and paid plans.

**Is there a mobile app?**

Yes, Lumo has iOS and Android apps in addition to the web app.

**How long are chats kept?**

On the free plan, Proton's help page says chats are saved for 7 days only. Guest conversations are erased when the session ends.