Chatbots compared on privacy
Using AI assistants safely
ChatGPT, Gemini, Perplexity and Mistral Vibe train on your chats by default. Claude, Duck.ai, Brave Leo and Proton Lumo do not. Copilot in the Microsoft 365 apps does not either. ChatGPT, Gemini and Mistral Vibe let you switch it off.
Which AI trains on your chats?
- Trains by default.
- Whether the provider uses your chats to improve its models while you do nothing.
- Where to switch it off.
- The page or the menu that holds the setting.
- Temporary chat.
- A chat that stays out of your history and out of training.
- How long it is kept.
- The term the provider names for keeping what you type.
- Where it runs.
- The country or region the provider names for its servers.
- Free version.
- Whether you can use the assistant without paying.
| Assistant | Trains by default | Where to switch it off | Temporary chat | How long it is kept | Where it runs | Free version |
|---|---|---|---|---|---|---|
| ChatGPT | Yes, until you switch it off | privacy.openai.com under "do not train on my content" | Yes. A Temporary Chat is left out of training | not stated | not stated | Yes, there is a Free plan |
| Claude | No, only when you allow it | Nothing to switch off. Check Settings > Privacy > "Help Improve our AI models" | not stated | Deleted chats leave back-end storage within 30 days. With training allowed they are kept de-identified for up to 5 years | not stated | Yes, there is a Free plan |
| Gemini | Yes, as long as Keep Activity is on | Turn off Keep Activity at myactivity.google.com/product/gemini | Yes. With Keep Activity off or in a temporary chat it is kept 72 hours | 18 months by default. 72 hours with Keep Activity off. Chats a reviewer has read are kept up to 3 years | not stated | Yes, there is a free plan |
| Microsoft Copilot (in the Microsoft 365 apps) | No | Nothing to switch off | not stated | not stated | not stated | The separate Copilot app is free with ads. Copilot in the Office apps needs a paid Microsoft 365 plan |
| Perplexity | Yes, according to its privacy policy | No switch is described in the privacy policy | not stated | As long as needed. The policy names no fixed term | not stated | Yes, there is a free tier |
| Duck.ai (DuckDuckGo) | No | Nothing to switch off | not stated | Chats sit on your own device. Model providers delete what they receive within 30 days. Shared chat links go after 30 days | Cloud providers of DuckDuckGo. The country is not named | Yes, free and without an account |
| Brave Leo | No | Nothing to switch off. Clear the local history at brave://settings/leo-ai | not stated | Not stored on Brave servers. Large prompts sit in cache for minutes. The local history stays encrypted on your device | not stated | Yes, with a daily prompt limit and no account |
| Mistral Vibe (formerly Le Chat) | Yes, until you switch it off | In the app under Settings > Data & Account Controls, turn off "Enable data sharing" | not stated | No term for chats is named | The European Union by default. A US endpoint is optional | Yes, a Free plan with a message limit |
| Lumo (Proton) | No | Nothing to switch off | not stated | Not stated. Saved chats are zero-access encrypted so Proton cannot read them | Europe, on servers Proton runs itself | Yes, a Free plan without a card |
- ChatGPT: openai.com, chatgpt.com, read on September 22, 2026
- Claude: privacy.claude.com, privacy.claude.com, privacy.claude.com, claude.com, read on September 22, 2026
- Gemini: support.google.com, gemini.google, read on September 22, 2026
- Microsoft Copilot (in the Microsoft 365 apps): support.microsoft.com, support.microsoft.com, read on September 22, 2026
- Perplexity: perplexity.ai, perplexity.ai, read on September 22, 2026
- Duck.ai (DuckDuckGo): duckduckgo.com, duck.ai, read on September 22, 2026
- Brave Leo: brave.com, brave.com, read on September 22, 2026
- Mistral Vibe (formerly Le Chat): help.mistral.ai, help.mistral.ai, help.mistral.ai, help.mistral.ai, mistral.ai, read on September 22, 2026
- Lumo (Proton): proton.me, proton.me, read on September 22, 2026
For your business
What each provider says about staff input on a business plan. Whether it trains on it, what an administrator can set and where the data sits.
- ChatGPT Business does not train on your business data by default. OpenAI supports a data processing addendum.
- Claude Team does not train on your content by default, but the data is stored in the United States.
- Microsoft 365 Copilot Business keeps EU traffic inside the EU Data Boundary. Models from Anthropic are currently outside it.
- Gemini in Google Workspace does not train on your content without permission. You can pick the EU for storage.
- Mistral Vibe Team trains on your input by default, so an administrator has to switch that off.
- Lumo Professional keeps your conversations confidential, and Proton runs it from Europe rather than the United States.
| Assistant | Plan | Trains on your business data | What an admin can set | Where the data sits |
|---|---|---|---|---|
| ChatGPT Business | Business (Standard seat), from 2 users | No, not by default | A data processing addendum is available for enterprise data handling | Storage in Europe is named for Enterprise, Edu, Healthcare and the API. Business is not on that list |
| Claude Team | Team (Standard seat), from 2 users | No, not by default | The data processing addendum sits in the commercial terms of service | Data is stored in the US. A choice of location is named for the API and Enterprise only |
| Microsoft 365 Copilot Business | Copilot Business add-on to an eligible Microsoft 365 plan | No | Microsoft points to its Data Protection Addendum and the product terms | EU traffic stays inside the EU Data Boundary. Models from Anthropic are currently outside it |
| Gemini in Google Workspace | Business Starter, Standard or Plus | No, not without permission | The privacy hub points to the Cloud Data Processing Addendum | You can pick the EU or the US. Google does not say which plans carry that choice |
| Mistral Vibe Team | Team (formerly Le Chat Team) | Yes by default. An administrator can switch it off for the whole organisation | Turn off "Allow your interactions to be used to train our models" in admin.mistral.ai | The European Union by default |
| Lumo Professional (Proton) | Lumo Professional | No | Proton has one data processing agreement for its services | Europe and Switzerland. Proton AG sits in Switzerland and that is outside the EU |
- ChatGPT Business: openai.com, openai.com, read on September 22, 2026
- Claude Team: claude.com, privacy.claude.com, privacy.claude.com, read on September 22, 2026
- Microsoft 365 Copilot Business: learn.microsoft.com, microsoft.com, read on September 22, 2026
- Gemini in Google Workspace: knowledge.workspace.google.com, workspace.google.com, read on September 22, 2026
- Mistral Vibe Team: help.mistral.ai, help.mistral.ai, help.mistral.ai, read on September 22, 2026
- Lumo Professional (Proton): proton.me, proton.me, read on September 22, 2026
Two assistants, side by side
- Proton Lumo vs ChatGPT: who trains on your chats?
- Proton Lumo vs Mistral Vibe: who trains by default?
- Proton Lumo vs Gemini: who may read your chats?
- ChatGPT vs Claude: which one trains on your chats?
- ChatGPT vs Gemini: who keeps your chats longest?
- ChatGPT vs Copilot: which one trains on your work?
- ChatGPT vs Perplexity: can you switch training off?
- ChatGPT vs Duck.ai: who sees your questions?
- ChatGPT vs Brave Leo: who stores your prompts?
Frequently asked questions
Does ChatGPT train on my chats?
Yes, until you switch it off. OpenAI writes that ChatGPT improves by training on the conversations people have with it. That happens unless you opt out. The switch sits at privacy.openai.com.
Which AI assistants do not train on your chats?
Claude, Duck.ai, Brave Leo and Proton Lumo leave your chats out of training by default. Copilot in the Microsoft 365 apps does the same. Brave writes that it does not use your conversations for model training. Claude trains only when you allow it.
How long does Gemini keep my chats?
Gemini keeps your activity for 18 months by default. With Keep Activity off it is 72 hours. Chats that a human reviewer has read are kept for up to three years.
Is Proton Lumo free?
Yes, Lumo has a Free plan and it needs no card. Proton runs the models on servers it controls in Europe. Saved chats are zero-access encrypted and Proton cannot read them.
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