Lumo

Lumo is a privacy-first AI assistant from Proton that answers questions, writes and analyzes files while keeping chat history protected with zero-access encryption. Proton built it for people who want the convenience of a ChatGPT-style assistant without handing their conversations to a company that profiles users or trains on their data. Its main difference is that privacy promise, backed by Proton's track record with encrypted email and storage.

What is Lumo used for?

Lumo handles the same everyday jobs as other assistants, with an emphasis on material people would rather keep private.

• Asking questions and getting answers with optional web search
• Drafting, rewriting and summarizing emails, contracts and documents
• Uploading files, or linking files and folders from Proton Drive, for analysis
• Helping with code and technical questions
• Generating images for personal or marketing use
• Organizing work into projects and custom Lumos for repeat tasks

Who Lumo is best for

Lumo suits existing Proton users, journalists, lawyers, therapists, healthcare and finance professionals, and anyone uneasy about how mainstream chatbots handle data. Lumo for Business targets teams that need confidential AI for drafting contracts or analyzing data. Power users who want the newest frontier models, plugins and deep app integrations may find mainstream assistants more capable.

Lumo pricing

Lumo has a free plan at $0 that requires no credit card and can be used without creating an account, with limits on Max model usage, messages, chat history, image generations, one project and custom Lumos. Lumo Plus costs $12.99 per month on monthly billing or $9.99 per month billed at $119.88 every 12 months, and adds more Max model usage, more messages and history, more image generations, and unlimited projects and custom Lumos. A 30-day money-back guarantee applies. Lumo for Business is available as Lumo Professional or within Proton Workspace. Prices are from Proton's Lumo pricing page as of October 2026, and local currency options include CHF and EUR.

Limitations to keep in mind

• Free usage caps can be reached quickly during heavy sessions
• Lumo does not match the plugin and integration ecosystems of larger assistants
• Privacy protections cover stored chats; check Proton's documentation for how web search requests are handled
• Some features work best if you already use Proton Drive

Lumo vs alternatives

ChatGPT and Claude offer stronger reasoning, more integrations and richer voice and agent features, and they are the better choice when capability matters more than privacy. Brave Leo AI is a privacy-focused assistant built into the Brave browser. Vibe (Mistral) is another European option with a broader feature set. Lumo wins when encrypted chat history and a no-training policy are requirements, especially for people already in the Proton ecosystem.

Tips for getting started with Lumo

Try Lumo without an account first to see whether answer quality fits your work. Turn on web search only for questions that need current information. If you use Proton Drive, link the relevant folder to a project so Lumo can reference files without repeated uploads.

Lumo FAQ

Is Lumo free?

Yes. Lumo has a free plan you can use without a Proton account. Lumo Plus costs $12.99 per month, or $9.99 per month on yearly billing.

Does Lumo use my chats to train AI?

No. Proton says Lumo never uses conversations to train AI and protects chat history with zero-access encryption so only you can read it.

Is Lumo safe to use with company data?

Proton offers Lumo for Business for confidential team use, with its privacy and compliance information in the Proton trust center. Review it against your own policies.

What is the best alternative to Lumo?

Brave Leo AI is a close privacy-focused alternative, while ChatGPT is the default choice when you want maximum features over privacy.