Lumo review

Lumo is the alternative for people who left ChatGPT because of privacy and want that promise in writing. Proton, the company behind Proton Mail and Proton VPN, says Lumo keeps no logs of prompts or replies, stores saved conversations with zero-access encryption so only your device can read them, never uses your data to train AI models and does not share it with advertisers or governments. The code is open source, and Lumo runs as a European service under GDPR. The free tier includes limited messages, chat history, image generations and Max model usage, plus one project. Lumo Plus costs $9.99 per month billed annually or $12.99 monthly and raises those limits, with unlimited projects and custom Lumos and a 30-day money-back guarantee. The trade-off is capability: Proton does not name the underlying models on its product page and documents far fewer tools and integrations than Claude or Gemini, so Lumo fits private everyday questions better than heavy work.

Who it is for

ChatGPT users who want the strongest privacy guarantees and a European provider.

Price

Free plan; Lumo Plus $9.99 per month billed annually or $12.99 monthly.

Lumo Plus US$9.99
Quoted from the vendor pricing page on November 10, 2026.

Key features

• Saved chats protected with zero-access encryption
• No logs of prompts or replies, per Proton
• Open source code that anyone can inspect
• Image generation, projects and custom Lumos
• Lumo for Business for teams

Strengths and weaknesses

• Strength: Proton states it never uses chats to train AI models
• Strength: Based in Europe and subject to GDPR
• Strength: 30-day money-back guarantee on Plus
• Weakness: Proton does not name the underlying models on the product page
• Weakness: The free tier allows only one project and limited chat history
• Weakness: Fewer integrations than the larger assistants

Key facts

• Free plan: Yes, limited messages, image generations and 1 project
• Lumo Plus: $9.99 per month billed annually, $12.99 monthly
• Encryption: Zero-access encryption for saved chats
• Refunds: 30-day money-back guarantee

Where it ranks

Lumo is No. 9 in our Best ChatGPT Alternatives verdict.