Most private AI assistant: 10 AIs checked (2026)
Short answer: the most private AI assistant is one that runs on your own computer, because your chats never reach anyone's server, so there is nothing to train on, keep or review. Among cloud assistants, 5 of 9 train on your chats by default on a free personal account; turning training off helps, but your chats still travel to the company, and feedback, human review and old data still count.
Three levels of "private"
- Doesn't train on your chats. Good, but your chats are still stored on the company's servers, and people there may read some of them.
- Doesn't keep your chats. Rarer: even "temporary" modes keep chats for a while for abuse checks (ChatGPT's Temporary Chats are deleted after 30 days).
- Your chats never leave your PC. Only possible when the AI itself runs on your computer. Nothing to train on, nothing to keep, nobody to read it.
The 10 assistants, checked
From each company's own help and privacy pages, for a free, personal, adult account. Training rules checked 18 October 2026; Temporary Chat retention re-checked 23 October 2026.
| Assistant | Trains on your chats? | What else to know | Your chats go to |
|---|---|---|---|
| ChatGPT | Yes, by default; switch off "Improve the model for everyone" | Thumbs up/down can still send the whole chat for training; Temporary Chats aren't used and are deleted after 30 days (OpenAI) | OpenAI's servers |
| Gemini | Yes, while Keep Activity is on | Human-reviewed chats kept up to 3 years, even if you delete activity (Google) | Google's servers |
| Claude | Only if you allow it | If allowed, chats kept up to 5 years (Anthropic) | Anthropic's servers |
| NotebookLM | No, unless you send feedback | With feedback, uploads can be reviewed and kept up to 3 years (Google) | Google's servers |
| Microsoft Copilot (new app) | Not stated | The opt-out is described only for the old app (Microsoft) | Microsoft's servers |
| Perplexity | Yes, by default | Turning "AI data retention" off doesn't remove earlier data (Perplexity) | Perplexity's servers |
| Mistral Le Chat | Yes, by default | Feedback is used whatever you choose (Mistral) | Mistral's servers |
| DeepSeek | Yes, by default (de-identified) | Switch off "Improve the model for everyone" (DeepSeek) | DeepSeek's servers |
| Meta AI | Yes | In the EU you can object with Meta's form (Meta) | Meta's servers |
| GreenCube (on your PC) | No | "We never receive your chats, files, memories or images"; Online search, off at every start, sends search terms (privacy) | Nowhere: your PC |
Every row in detail, with how to switch each one off: which AI doesn't train on your chats. ChatGPT plan by plan: does ChatGPT train on your data?
Making a cloud assistant as private as it gets
- Switch training off before you paste anything sensitive, not after: what's already used stays used.
- Don't rate sensitive chats. A thumbs up or down can send the whole conversation for review, even with training off.
- Use the temporary or incognito mode where there is one, knowing it's still kept for a while.
- Use a school or work account if you have one: they're usually left out of training by default.
A private AI assistant on your own PC
An AI that runs locally is a file on your computer: your questions are answered by your own graphics card or processor, so there is no company in the middle. The cost is speed, which depends on your PC. We measured GreenCube on 10 real PCs:
| Your PC | Writes |
|---|---|
| 8 GB laptop, no graphics card | 5–7 tokens/s, about reading speed |
| 16 GB laptop, no graphics card | 14–18 tokens/s |
| Gaming PC with a 6 GB+ card | 37–76 tokens/s on most cards |
Free and private
LM Studio, Jan, Ollama and GPT4All run locally and cost nothing; you pick a model yourself. 12 offline AI apps compared.
Private without setup
GreenCube (Windows, €9.99 once) picks the model that fits your PC and also reads PDFs and photos and makes pictures.
For a team
A self-hosted chat page on your own server keeps chats in-house: Open WebUI and its alternatives.
Check it yourself
Turn the Wi-Fi off and ask something. If it answers, the AI is on your PC. How to check on Windows.
How we checked
We read each company's own help center and privacy pages for a free, personal, adult account, not news or reviews, and linked the page each fact comes from. Where a page doesn't answer, as with Microsoft's new Copilot app, we say "not stated". We make GreenCube, so we've stuck to facts anyone can check. Policies change often; we re-check every month.
Questions
What is the most private AI assistant?
One that runs on your own computer, because your chats never reach a company server. GreenCube, LM Studio, Jan and GPT4All work this way. Among cloud assistants, NotebookLM says it doesn't train on your uploads unless you send feedback, and Claude only trains if you allow it, but your chats still go to their servers.
Which AI assistants train on your chats by default?
Of the 9 cloud assistants we checked for a free personal account in October 2026, 5 train on what you type by default: ChatGPT, Perplexity, Mistral Le Chat, DeepSeek and Meta AI. Gemini trains while Keep Activity is on; Claude only if you allow it.
Is a private AI assistant really private if I turn off training?
Not fully. Feedback you give can still be used, some services keep chats for human review (Gemini keeps reviewed chats up to 3 years), and data already used isn't removed. Turning training off only covers what you send afterwards.
Is there a free private AI assistant?
Yes: LM Studio, Jan, Ollama and GPT4All are free and run the AI on your own PC, so nothing is sent anywhere; you choose and download a model yourself. GreenCube costs €9.99 once and picks the model for you.
Can a private AI assistant work offline?
Yes, if it runs locally. After the first download, GreenCube and the other local apps answer with the Wi-Fi off. Cloud assistants can't work offline.
Your own AI, on your own PC
GreenCube runs on your computer: no usage limits, no subscription, works without internet. €9.99 (US$9.99), paid once.
Get GreenCube