Lumo The European alternative to ChatGPT

Lumo is an AI chat assistant from Swiss company Proton AG, known for Proton Mail and Proton VPN. People use it to ask questions, draft text, explain code, summarize documents or generate images. The service is built on open-source language models and focuses on keeping conversations confidential. Lumo can be used in a free tier without an account; a Proton account stores the chat history and raises the usage limits. It is available through the browser as well as mobile apps for Android and iOS.

Lumo is operated by Proton AG, based in Geneva, and is subject to Swiss data protection law. The open-source language models run on Proton's own hardware in European data centers; according to the provider, AWS, Google Cloud and Microsoft Azure are not used. The model server is stateless and keeps no logs of conversations, so the previous history is re-sent with each request. The chat history is additionally stored with zero-access encryption, so neither Proton nor third parties can read it.

Lumo is designed for confidentiality: conversations are not logged and are not used to train models, whereas many widely used assistants analyze chats by default. Lumo's app code is open source and therefore independently verifiable. The chat history is stored with zero-access encryption that only the user can unlock with their account password. Functionally, Lumo offers text generation, research, coding help and image generation; the paid Lumo Plus tier increases usage limits, model access and image generation.