Proton Lumo

Lumo is an AI assistant from Proton, a Geneva-based company behind Proton Mail, Proton VPN, and Proton Drive. Its key difference from ChatGPT and Gemini is privacy: conversations are not used to train models or shared with advertisers, while chat history is stored with zero-access encryption—only the account owner can read it. The application code is open source.

What It Can Do

• Chat assistant. Answers questions, writes and translates texts, reviews and checks code, and analyzes data and reports.
• Internet search. Adds up-to-date information from the web to its response when requested.
• Files. Upload documents for analysis and connect files and folders from Proton Drive.
• Image generation. Creates images from descriptions and edits them; the limit depends on the plan.
• Projects and custom assistants. Project-based chats and customizable Custom Lumos.
• Incognito mode. The chat is deleted immediately after closing it.
• No registration required. You can use it as a guest, including through Tor; after signing in, you get more questions and chat history.

Models and Privacy

Lumo runs on open models (Qwen, GLM, Apertus, and image-generation models) on Proton servers in Europe; each request is automatically routed to the model best suited to the task. Requests are transmitted over TLS and encrypted so that only Lumo servers can decrypt them; chat logs are not kept. The service complies with GDPR, operates outside US jurisdiction, and contains no ads.

Plans

Plus comes with a 30-day money-back guarantee. Lumo for Business is available for companies (HIPAA, GDPR, ISO 27001).

Apps: the web version at lumo.proton.me, iOS, and Android. The interface and responses are available in 11 languages, including Russian.