We make Pinku, an AI chat app that runs on the iPhone, and it is one of the options below. Most of this page applies whichever app you use.
The short answer
A cloud chatbot is a service run on someone else's computers. What you type is stored on your account, can be used to train models unless you switch that off, and some of it can be read by people. Google is the most direct about it: its Gemini privacy hub says, in so many words, “Please don't enter confidential information that you wouldn't want a reviewer to see or Google to use to improve our services” (Gemini Apps Privacy Hub, read 23 October 2026). The same page says chats a human reviewed are kept for up to 3 years, disconnected from your account, even if you delete them.
OpenAI deletes a chat you delete within 30 days, with exceptions for chats already de-identified or kept for security or legal reasons, and on Free, Plus and Pro it may train on your chats unless you turn off Improve the model for everyone. Even then, a thumbs up or down sends the whole conversation for training. We read and quoted every one of those policies in what AI chatbots keep when you delete your chats.
What the App Store privacy labels say (checked 23 October 2026)
Every iPhone app has to declare what it collects. These are the developers' own declarations, which Apple shows but does not verify:
| App | Data linked to you, as declared | Purposes that stand out |
|---|---|---|
| ChatGPT (version 1.2026.286) | Health & Fitness, Location, Contact Info, User Content, Search History, Identifiers, Usage Data, Diagnostics | User Content is listed for Analytics and App Functionality; Health & Fitness for Analytics and Product Personalisation; Usage and Advertising Data for Third-Party Advertising |
| Google Gemini | Includes precise location, contacts, search and browsing history, user content and identifiers | Developer's advertising or marketing, analytics, product personalisation |
| Pinku (version 1.1) | Purchases and an identifier (user ID) | App Functionality only: recording an App Store purchase |
A label is not proof of anything bad; it tells you what can leave the phone. With a cloud chatbot, your conversations are part of that by design.
What not to paste into any cloud chatbot
- Passwords, one-time codes, recovery keys, full card or bank numbers.
- ID, passport, social security or health insurance numbers.
- Medical results, legal documents or contracts with your name, address or case number still on them.
- Other people's private details: a friend's diagnosis, a colleague's salary, screenshots of someone else's messages.
- Work material your employer has not cleared for AI tools.
Asking “what does a high LDL mean?” is fine. Pasting the lab report with your name and date of birth is the part to avoid.
Step by step
- Sort the question first. General knowledge, writing help and code without secrets can go to any cloud chatbot. Anything that identifies you or someone else should be rewritten, or kept on the phone.
- Strip identifiers before pasting. Remove names, addresses, dates of birth, account and case numbers. Replace them with placeholders such as [NAME]; the answer will be just as useful.
- Turn off training in ChatGPT. In ChatGPT open Settings, Data controls and turn off Improve the model for everyone (OpenAI help). Do not press thumbs up or down on a sensitive chat: that sends the whole conversation for training even with the setting off.
- Use temporary chats for one-off questions. ChatGPT temporary chats are not in your history but may be kept up to 30 days. Gemini temporary chats, and chats with Keep Activity off, are kept 72 hours and are not used to improve Google AI with human reviewers.
- Delete what you no longer need. Deleted ChatGPT chats are erased within 30 days, with exceptions (OpenAI). Gemini auto-deletes after 18 months by default; you can set 3 months. Chats a reviewer already read stay up to 3 years.
- Keep the truly private things on the phone. Use an AI that runs on the device, such as Pinku. Download a model once, then turn on airplane mode and ask: if it answers, nothing you typed left the iPhone.
Keeping it on the phone: the options
An on-device model is much smaller than ChatGPT, so it is weaker at hard questions, cannot browse the web and remembers less of the conversation. For rewriting a private message, summarising a document you paste in or thinking aloud about something personal, it is enough, and there is no server to trust.
- Pinku (version 1.1, 22 October 2026). Runs 11 open models on iPhone or Mac with Apple's MLX, from Qwen3 0.6B (0.4 GB) to Qwen3 8B (4.7 GB); works in airplane mode once a model is downloaded; no account; chats saved only on the device. Free with Gemma 3 1B; Pinku Pro (yearly or a one-time purchase) lets you choose any model and adds custom instructions, on-device dictation and read aloud. Requires iOS 18.6. It is weaker than a cloud model, and only lists the models your device has the memory for.
- Locally AI by LM Studio (free, 1.66.0): runs Llama, Gemma, Qwen and others on iPhone and iPad with MLX, no login.
- Private LLM ($4.99 one-time, 1.9.16): local models on iPhone and iPad.
- PocketPal AI (free, 1.20.1): runs models on the device for offline chat.
- Enclave (free, 1.77.0): local assistant; its current version requires iOS 27.
- Apple's own model: on iPhones with Apple Intelligence, the Shortcuts action Use Model set to On-Device works without a network connection.
Versions and prices from the US App Store on 23 October 2026. We compared these apps in detail, including where they beat Pinku, in the best private AI apps that keep your chats on your iPhone. To check any app yourself, see how to check whether an AI chat app really keeps your chats on your iPhone.
Sources
- Google, Gemini Apps Privacy Hub, read 23 October 2026.
- App Store privacy labels of ChatGPT, Google Gemini and Pinku, US store, read 23 October 2026.
- OpenAI help centre on chat retention and model training, quoted in our 20 October 2026 article.
- Apple, Shortcuts User Guide: Use Model.
Questions people ask
Is it safe to tell ChatGPT private things?
For general questions, yes. For anything that identifies you or someone else, no: chats are stored on your account, may be used for training unless you turn it off, and the companies' own pages tell you not to share confidential information. Remove names and numbers first, or use an AI that runs on your phone.
Can people at OpenAI or Google read my chats?
Google says human reviewers read some Gemini chats and keeps those for up to 3 years, disconnected from your account. OpenAI keeps chats until you delete them and may review them for safety. Neither is a private diary.
Does deleting a ChatGPT chat delete it for good?
It disappears at once and OpenAI says it is erased within 30 days, unless it was already de-identified or must be kept for security or legal reasons.
Does a temporary chat keep my data private?
Partly. ChatGPT temporary chats are not in your history but may be kept up to 30 days. Gemini temporary chats are kept 72 hours. Both still go to the company's servers.
How can I use AI without my chats leaving my phone?
Use an app that runs the model on the device, such as Pinku, Locally AI, Private LLM or PocketPal AI. Test it in airplane mode: if it still answers, the conversation stays on the phone.