Lumo is Proton’s first AI-powered assistant offering familiar capabilities like document summarization, code generation, translation, email drafting, and brainstorming—while upholding uncompromising privacy standards.
Built by the same Swiss nonprofit that created Proton Mail, VPN, Drive, and Pass, Lumo is now available via web, iOS, and Android apps.
Rather than training proprietary models, Proton orchestrates several leading open-source language models on its EU‑based infrastructure:
- Mistral Small 3, Nemo
- OpenHands 32B
- OLMO 2 32B from the Allen Institute
These models are selected per-context: for example, OpenHands handles coding-related prompts while others address general conversation or summarization
Data sovereignty: Operates under European/Swiss jurisdiction; infrastructure is migrating to EU to avoid proposed Swiss mass surveillance laws, investing over €100 million into a “EuroStack” alternative to Big Tech A
Alternative to surveillance-driven AI: Aiming to disrupt surveillance capitalism by offering AI that serves people, not profiles them
Privacy & Encryption Architecture
Zero‑logs policy: No server‑side record of user prompts or responses is retained. All saved chats are encrypted so tightly that even Proton cannot decrypt them.
Zero‑access encryption: Conversations are encrypted client‑side and stored with keys only on user devices—ensuring Proton or any third party cannot access them
Secure transmission: API requests and responses use TLS, and prompts are symmetrically encrypted then decrypted only on Proton’s GPU servers at inference time
Features & Workflows
● Chat Interface
- Can be used without signup—free limited chats allowed as a guest.
- With a Proton account (Free tier), users unlock encrypted chat history, favorites, and limited chat storage.
- Optionally, ‘Ghost Mode’ lets you end a session without saving anything—no trace left ✖️ history kept.
● Web Search (Optional)
- Disabled by default; must be manually enabled to preserve privacy.
- When turned on, uses privacy‑friendly search engines, retrieving live concise responses without compromising anonymity.
● File Uploads & Proton Drive Integration
- Supports uploading documents (e.g., PDFs, text); analysis is temporary and secure.
- Direct integration with Proton Drive lets you attach encrypted files in chats—also processed securely without telemetry or logging.
● Supported Languages
- Currently supports English, Spanish, French, German, Italian, Portuguese, Dutch, Russian, Chinese, Japanese, and Korean
Open‑source foundation: Lumo runs on open-source LLMs (no closed licensing; everything from data pipelines to model code is IG‑verifiable)
Lumo: Privacy-first AI assistant where chats stay confidential