Best Private AI Assistants (2026): 6 Tools That Don't Train on Your Data
Many AI assistants are free for a reason. With some, your conversations are the price: depending on the plan and your settings, they may be stored, reviewed, and in some cases used to help train the next model.
For a quick question that does not matter. For a salary on a contract, a patient symptom, an unreleased product, or a client's file, it matters a lot. A 2025 court order in NYT v. OpenAI required OpenAI to preserve user conversations, including ones people had already deleted, overriding its standard 30-day deletion window. The lesson is simple: if the data exists, it can be demanded.
This guide compares the AI assistants that take privacy seriously in 2026, so you can pick the one that fits how you actually work.
What "private" actually means
Marketing pages love the word "private." It means nothing on its own. Four things decide whether an AI assistant is genuinely private:
- Data retention. How long are your conversations stored after you get an answer? The strongest answer is zero. The request is processed, answered, and discarded.
- Training. Are your inputs used to train the model? On a real private tool the answer is never, in writing, not a toggle you have to remember to flip.
- Jurisdiction. Where is your data processed, and whose laws apply? For European users and anyone handling regulated data, processing inside the EU is the difference between compliant and not.
- Identity. Does the tool know who you are? Anonymous or account-free access removes a whole category of risk.
Price and model quality matter too, but they are table stakes. We ranked on the four points above first.
Quick verdict: best private AI by use case
| If you are... | Pick |
|---|---|
| A business or regulated team in the EU | Wysor |
| An individual already in the Proton ecosystem | Proton Lumo |
| A Kagi search subscriber | Kagi Assistant |
| Living inside your browser | Brave Leo |
| Wanting open, uncensored models | Venice AI |
| Needing fully offline, on your own machine | Local models (Ollama / Jan) |
1. Wysor: best for EU businesses and regulated work
Wysor is a private AI workspace built in Germany for people who cannot afford to leak data: clinics, law firms, finance teams, and any business that handles client or patient information.
Privacy model. Zero data retention is the default, not an upgrade. Every model Wysor routes to (Claude, GPT-5, Gemini, Perplexity, and a range of open-source models) is wrapped in a dedicated agreement that sets retention to the technical minimum, which for most providers is zero. Your data is never used for training, on any plan. Many models run on EU infrastructure, so your conversation is answered in Europe and does not need to leave it. On the iOS app, voice transcription runs on your device.
Why it stands out. Most private assistants give you one model and one feature. Wysor is a full workspace: multi-model chat, private email assistance, voice transcription, document generation, and research across public legal and medical document collections (court rulings, official gazettes, peer-reviewed sources, and regulatory filings). For regulated industries it does the compliance plumbing that normally requires a procurement cycle, available the moment you sign up.
Best for. Businesses, healthcare, legal, and finance teams in the EU that need privacy in writing, not a privacy policy that can change next quarter.
Limitations. It is a workspace, not a single-purpose chatbox, so there is slightly more to it than a bare prompt box. There is a free plan, with paid plans for heavier use.
See how Wysor handles your data →
2. Proton Lumo: best for individuals in the Proton ecosystem
From the makers of Proton Mail, Lumo is a privacy-first assistant for individuals.
Privacy model. Proton says Lumo uses zero-access encryption so your chat history is readable only on your devices, keeps no logs, does not train on your conversations, and offers a "Ghost mode" for chats that disappear. It runs on open-source models, so the underlying technology can be independently inspected.
Best for. Individuals who already trust Proton for email and want a consumer assistant from the same company.
Limitations. At the time of writing, Proton's published plans pair a limited free tier with a paid tier (Lumo Plus) for heavier use. Check Proton's pricing page for current limits and prices. It is a personal-productivity tool rather than a business workspace, and it focuses on its own model lineup rather than a choice of frontier models.
3. Kagi Assistant: best for Kagi search subscribers
Kagi, the paid private search engine, bundles an AI assistant for its members.
Privacy model. Kagi says it does not train on your conversations, does not forward your account identity to the model providers, and acts as an anonymous proxy. Conversation threads are deleted after about a day by default.
Best for. People who already pay for Kagi search and want their AI to live in the same privacy-respecting account.
Limitations. It requires a Kagi subscription, so it is not a standalone option. Like the others here, it is a personal tool rather than a team or compliance product.
4. Brave Leo: best for in-browser use
Leo is the AI assistant built into the Brave browser.
Privacy model. Brave says Leo routes requests through an anonymizing proxy, does not retain conversations, and ties nothing to your identity. A free tier runs open models, with frontier models on a paid plan.
Best for. People who live in their browser and want an assistant a click away on any page, without a separate app or login.
Limitations. It is tied to the Brave browser, and it is built for browsing tasks rather than deep document work or team collaboration.
5. Venice AI: best for open, uncensored models
Venice is a privacy-focused assistant built around open-source models.
Privacy model. Venice says conversations are stored locally in your browser rather than on its servers, and that it does not log your chats. It leans on open models, which appeals to people who want fewer content restrictions and more transparency about what is running.
Best for. Power users who want open models, minimal filtering, and local storage of their own history.
Limitations. Open models can trail the top frontier models on the hardest tasks, and local-only history means you manage your own backups. Not aimed at regulated or business compliance.
6. Local models (Ollama, Jan): best for fully offline
If the data must never leave your machine, run the model on it.
Privacy model. Tools like Ollama and Jan run open-source models entirely on your own hardware. Nothing is sent anywhere. There is no provider, no retention, and no jurisdiction question, because there is no network call.
Best for. The most sensitive work, air-gapped setups, and anyone who wants absolute control.
Limitations. You need a capable machine, the best local models still trail the frontier ones, and you give up the conveniences of a hosted product: sync, mobile apps, search, email, and team features. For most businesses this is a complement to a hosted private tool, not a replacement.
Side-by-side comparison
| Retention | Trains on you | Processed in EU | Account needed | Price | |
|---|---|---|---|---|---|
| Wysor | Zero for most providers | Never | Yes, many models | Yes | Free plan + paid |
| Proton Lumo | No logs (per Proton) | Per Proton, no | Yes | Yes | Free tier + paid |
| Kagi Assistant | Short expiry | Never | No | Yes (Kagi sub) | Paid |
| Brave Leo | Not retained | No | No | No | Free + paid |
| Venice AI | Local only | No | No | Optional | Free + paid |
| Local (Ollama/Jan) | None (offline) | No | On your machine | No | Free |
How to choose
- You run a business or handle regulated data in the EU. You need retention and no-training commitments in a contract, plus EU processing. Start with Wysor.
- You are an individual who wants a clean private assistant. Proton Lumo or Brave Leo, depending on whether you prefer an app or your browser.
- Privacy must be absolute and you have the hardware. Run a local model with Ollama or Jan.
The honest answer is that more than one of these can be right at once: a local model for the crown-jewel documents, and a hosted private workspace for everything else.
Frequently asked questions
What is the most private AI assistant? For absolute privacy, a local model on your own machine (Ollama or Jan) sends nothing anywhere. Among hosted tools, the strongest are those with zero data retention and no training on your data, processed in the EU. Wysor is built for that for business and regulated use; Proton Lumo is a strong consumer option.
Is ChatGPT private? It depends on the plan and your settings. On consumer plans (Free, Plus, and Pro), OpenAI uses your conversations to help train its models by default, unless you turn off "Improve the model for everyone" in Data Controls. Its Business, Enterprise, Edu, and API tiers are excluded from training by default. Separately, consumer ChatGPT data was placed under a 2025 court preservation order in NYT v. OpenAI. Check OpenAI's current terms for your plan.
Does Proton Lumo train on your data? Proton says no: it states that Lumo keeps no logs and does not use your conversations for training, and that it uses zero-access encryption so history is readable only on your devices. See Proton's current terms for the details.
What does "zero data retention" mean? Your request reaches the provider, the model answers, and the request and response are then discarded from the provider's systems. No logs, no backups, no training data. There is nothing left to subpoena or train on.
Can my business use a private AI and stay GDPR compliant? Yes, if the tool processes data in the EU, signs the right data-processing terms, and does not train on your inputs. That combination is exactly what Wysor is built to provide for businesses and regulated teams.
Keep reading
- ChatGPT vs Claude vs Gemini Privacy (2026): Which Is Safest?
- Complete Privacy: Your Data Never Leaves Your Control
- Shadow AI: When Your Employees Use ChatGPT Behind Your Back
- We Built the AI Workspace That Should Have Existed 3 Years Ago
Competitor descriptions reflect each provider's own publicly stated policies, terms, and pricing as of June 2026, and are provided for general comparison only. Features, prices, and terms change often and vary by plan and region. This is not legal advice. Always verify the current terms on each provider's own site before relying on them.
