People tell AI assistants things they would never post online: health questions, money worries, work secrets. This ranking looks only at privacy: whether your chats train the model by default, how long they are kept, whether people review them and how each company has handled privacy incidents.
| # | Name | Best for | Price |
|---|---|---|---|
| 1 | Lumo by Proton | Maximum privacy | Free tier · Paid plan |
| 2 | Duck.ai | Anonymous access to several models | Free |
| 3 | Claude | Writing, research and coding with clear training controls | Free plan · Paid plans |
| 4 | Mistral Le Chat | European alternative | Free plan · Paid plans |
| 5 | ChatGPT | Features and integrations | Free plan · Paid plans |
| 6 | Perplexity | Answers with sources | Free plan · Paid plans |
| 7 | Microsoft Copilot | Windows and Microsoft 365 users | Free · Microsoft 365 plans |
| 8 | Google Gemini | Google services users | Free · Google AI plans |
| 9 | Meta AI | Casual use in Meta apps | Free |
| 10 | Grok | Real-time X content | Free · Paid plans |
| 11 | DeepSeek | Not recommended for sensitive use | Free |
Launched by Proton in July 2025. Proton says Lumo keeps no server-side logs of conversations, does not train on your prompts and encrypts saved chats so only your device can read them. It runs on open-source models hosted in Europe and can be used without an account.
DuckDuckGo’s free AI chat sends your prompts to model providers from DuckDuckGo’s own address, strips identifying metadata and requires providers to delete chats within 30 days and not train on them.
Made by Anthropic. Since its August 2025 consumer terms update, Free, Pro and Max users choose whether their chats are used to improve Claude: if allowed, data is kept for five years; if not, the standard 30-day retention applies. Business and API use is not used for training.
From French company Mistral AI, which also releases open-weight models. Since September 2026, consumer plans use your inputs and outputs for training unless you opt out in settings.
OpenAI’s assistant is the most widely used. For consumer accounts, the “Improve the model for everyone” setting is on by default; turn it off in Settings › Data controls. Temporary Chats are not saved to your history and are deleted after 30 days.
An AI search engine that answers with linked sources, useful for research. Its “AI data retention” setting, on by default for Free, Pro and Max users, lets Perplexity use your data to improve its models; turn it off under Account settings › Preferences. Enterprise data is never used for training.
Built into Windows, Edge and Microsoft 365. Signed-in consumer users can turn off “Training on conversation activity” and “Training on voice conversations” in Copilot’s privacy settings.
For users 18 and over, Gemini’s Keep Activity setting is on by default and activity auto-deletes after 18 months. Some chats are reviewed by people and kept for up to three years, even if you delete your activity. With Keep Activity off, Google still keeps chats for 72 hours.
Built into Facebook, Instagram and WhatsApp. In June 2025 many users of the Meta AI app unknowingly published their chats to its public Discover feed through the share button.
From xAI and integrated with X. In August 2025, conversations shared with Grok’s Share button were found indexed by Google and other search engines, exposing sensitive prompts.
A Chinese AI company whose user data is stored in China. In early 2025, Italy’s data protection authority restricted it, Australia and Taiwan banned it on government devices, and US bodies including the Navy and NASA barred staff from using it.
Find the setting that controls whether your chats train the model and choose deliberately.
For sensitive questions, use modes that do not save history.
Keep passwords, ID numbers, client data and private details of other people out of prompts.
Shared links can become public and searchable.
AI can be confidently wrong. Check important facts with primary sources.
More live news on News Matrix →
Marie-Soleil Seshat Landry’s custom AI models on Poe and ChatGPT.
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Lumo by Proton and Duck.ai are the most private: Lumo keeps no server-side logs and encrypts saved chats, and Duck.ai anonymizes your prompts and requires providers not to train on them.
For consumer accounts, yes by default. Turn off “Improve the model for everyone” in Settings › Data controls, or use Temporary Chat.
Only if you allow it. Since Anthropic’s August 2025 update, Free, Pro and Max users choose. Business and API data are not used for training.
Avoid it for anything sensitive: its user data is stored in China, and several governments have restricted it on official devices.
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Topics: private AI chatbot, AI assistants privacy ranked 2026, Lumo Proton, Duck.ai, Claude privacy, ChatGPT training opt out, Gemini privacy, Mistral Le Chat, Perplexity, Copilot, Meta AI privacy, Grok privacy, DeepSeek data China
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