We make Pinku, an AI chat app that runs its models on the device, and we use it as the example. The checks work on any app.

When you type into ChatGPT, Claude or Gemini, the message travels to the provider's servers, and how long it is kept is set by the provider's policy (we summarised what they say in what AI assistants do with your conversations, with figures checked on 5 September 2026). An app that runs the model on your phone does not need to send the message anywhere. You can test whether an app behaves that way instead of taking its word for it.

Step by step

  1. Read the App Store privacy label. On the app's App Store page, scroll to App Privacy. "Data Not Collected" means the developer says it does not collect any data from the app. It is the developer's own declaration, not something Apple verifies, so treat it as a claim to test. Since 19 October 2026 Pinku's US page lists only purchase history and an anonymous user ID, used for Pinku Pro purchases; no chat content.
  2. Turn on App Privacy Report. Settings, Privacy & Security, App Privacy Report, Turn on App Privacy Report (iOS 15.2 or later). Apple says it starts gathering information only after you turn it on, and that the data is encrypted and stored only on your device.
  3. Use the app for a day or two, then look at its network activity. Open App Privacy Report and tap the app under App Network Activity. It lists the web domains the app contacted in the past 7 days. A cloud chat app will show its provider's servers. An app that runs the model on the device should show nothing, or only things you can explain, such as the one-time model download.
  4. Try airplane mode. Turn on airplane mode, open the app and ask a question. If it answers, the answer was generated on the device. If it says it needs a connection, it is sending your message to a server.
  5. Check where the chat is stored and how to delete it. A private app should say where chats live and let you delete them. In Pinku, chats stay on the device that wrote them, there is no sync, and deleting a chat deletes it from the phone.
  6. Know what these checks cannot show. App Privacy Report lists domains, not what was sent to them. A clean report does not prove the app is harmless and a long list does not prove it is not. It covers the last 7 days, so use the app first.

What this looks like in Pinku

Pinku runs open language models (Gemma, Llama, Qwen, DeepSeek-R1 distills, SmolLM3 and LFM2) on the iPhone, iPad or Mac through Apple's MLX framework. There is no account and no server of ours. The network is used to download a model the first time and for App Store purchases, so that is what you should expect to see, and nothing else, in App Privacy Report after you chat. Voice dictation, if you buy Pinku Pro, is recognised on the device.

The trade-off is capability: a model of 1 to 5 GB on a phone is clearly weaker than ChatGPT or Claude in the cloud, it cannot browse the web, and it does not read images or documents. Pinku is free to download, the six models up to 1 GB work without paying, and Pinku Pro ($9.99 on the US App Store, one time, no subscription) adds the larger ones. How to set it up and use it on a plane: how to use AI on iPhone without internet. Other apps that run a model on the device, ranked honestly: the best private AI apps for iPhone.

Questions people ask

How can I tell if an AI app sends my chats to a server?

Turn on App Privacy Report (Settings, Privacy & Security), use the app, and look at the domains it contacted. Also try it in airplane mode: an app that still answers is running the model on your device.

What does Data Not Collected mean on the App Store?

It means the developer declares that it does not collect data from the app. Apple shows it as the developer's declaration, not something Apple has verified, so it is worth testing.

Does App Privacy Report show what an app sends?

No. It shows which domains an app contacted and when, in the past 7 days, not the content. It is a good way to see whether an app talks to a server at all.

Is it safe to tell ChatGPT private things?

That depends on the settings and the plan; the provider's policy decides how long a chat is kept and whether people may review it. Our summary of the three big providers' policies, checked on 5 September 2026, is in the article linked above. If you do not want a message to leave your phone at all, use a model that runs on the device.

Does Pinku send my conversations anywhere?

No. Pinku has no account and no server of ours; chats are stored on the device. The network is used to download models and for App Store purchases.

Is a local AI as good as ChatGPT?

No. A model of 1 to 5 GB on a phone is clearly weaker, has a shorter memory and cannot browse the web. Its advantage is that nothing you type leaves the device.