Lumo AI Review: Proton's Private AI Tested (2026)

The Lumo AI review from Proton frames the assistant around privacy controls designed to prevent the company operating the service from reading user chats. Proton, the Swiss firm behind Proton Mail and Proton VPN, shipped Lumo 2.0 on June 30, 2026, rebuilding the assistant with features including a “thinking mode,” image generation, long-term memory, and faster responses up to 76%. The review says Lumo uses open-weight models Qwen 3.5 and GLM 5.2, routed on Proton-controlled servers rather than third-party cloud, and relies on zero-access encryption plus a no-logs policy. A free tier is available without an account, while Lumo Plus is priced at $12.99 per month (about $9.99 billed yearly), compared in the article with $20 tiers for ChatGPT Plus and Claude Pro. It also notes there is no native Mac app, only web and iOS, and references an independent audit calling it “the least open” open AI.