At WWDC 2026 Apple shipped a genuinely excellent assistant: a new Siri that reads your messages, photos and mail to actually help you. For its hardest requests it sends that personal context to the cloud. Ostler does the personal half on your Mac, where it never leaves. This is not local versus cloud. It is about where your life is kept.
Both Ostler and the new Siri answer questions about your own life by reading your own data. The difference is the path that data takes. Siri keeps simple requests on the device and sends the advanced ones to the cloud. Ostler keeps the personal layer on your Mac, full stop. Ostler keeps the one thing Apple just sent away: your personal memory.
| Ostler | Apple Siri AI | |
|---|---|---|
| Where your personal context is processed | On your Mac, locally | On-device, then Apple Private Cloud Compute and Google Cloud for advanced and visual requests |
| Does your personal memory leave the device | Never | Advanced and visual requests are processed in the cloud |
| Privacy model | Architecture – there is no cloud copy | Policy plus confidential computing and PCC attestation |
| Works fully offline | Yes | On-device tier only |
| A browsable, correctable, exportable record of your life | Yes – an owned graph and personal wiki | No – a built-in semantic index you cannot open |
| Cross-source breadth | 20 sources via GDPR exports, plus your Apple data | Your Apple apps and on-screen content |
| EU iPhone and iPad availability | Yes – iOS Companion paired to your Mac Hub | Delayed, no timeline |
| EU Mac availability | Yes | Yes (macOS 27) |
| Open-ended world reasoning | Local models, plus web search when you ask | Frontier-class Apple models, distilled from Gemini |
| Built in, zero setup, no charge | A paid app you install | Yes, on your Apple devices |
Ostler is an Apple-native product. It reads your Contacts, Messages, Calendar and Mail through Apple's own frameworks, runs on your Mac, and pairs with an iPhone. We use Apple's platform every day and we think the new Siri is the best assistant Apple has ever shipped. For most people who trust Apple's privacy promise, it will be the default and it will be good.
Ostler is for the part Apple has, in effect, sent away: a personal memory of your life that is kept on your own machine and answered from there. On the Mac, where Siri AI is available, the two sit happily side by side. Siri is the system assistant. Ostler is the private record underneath it.
Credit where it is due, and no strawman. The new Siri runs a three-tier system: simple requests stay on the device using Apple's own models; moderately complex ones go to Apple's Private Cloud Compute; and the heaviest reasoning routes to Apple's most capable model – custom-built for Apple silicon and refined using outputs from Google's Gemini frontier models – running on Nvidia GPUs hosted in Google's cloud, wrapped in hardware confidential computing. Apple is explicit that it uses none of Google's deployed Gemini models, none of Google's client code, and no Google Search underneath: the contribution is distillation, not adoption. Apple's stated guarantees for that cloud tier are that your data is never stored, is used only for the immediate request, and runs on production software that independent researchers can inspect.
That is a serious privacy effort, and we are not going to pretend otherwise. But notice what it is: a set of promises and protections about data that has left your device. The advanced requests, the visual understanding, and your Siri conversation history all travel beyond the Mac in your hands. The protection is real. The custody has changed.
Apple's privacy story is a strong policy: sincerely meant, attested by Private Cloud Compute, wrapped in confidential computing. You still have to trust that your personal context, once sent, is handled as described.
Ostler's privacy story is architecture. Your personal context is never sent. The assistant, the local models, and your knowledge graph all run on your Mac. Pull the network cable and Ostler still answers from your own data, because there is no cloud copy to reach for.
Both are legitimate. If you are happy to trust Apple's policy, Siri AI is excellent and it is already on your devices. If you would rather the most personal data category that exists – your relationships and conversations – simply never leave the machine, that is the line Ostler is built on.
Apple just proved the demand: the world's loudest privacy brand has invested heavily so that Siri can read your life and help you with it. The only open question is custody. Do you want that personal layer protected by a promise once it reaches the cloud, or kept somewhere it never goes? Siri AI is a system assistant with cloud reach. Ostler is a private memory that stays home.
This is the sharpest practical difference today. Apple has said the new Siri AI is delayed on iPhone and iPad in the EU with no timeline, because of how the Digital Markets Act would require it to open up device access. It does ship in the EU on the Mac (macOS 27), but not on the iPhone or iPad.
Ostler's iOS Companion is an ordinary App Store app. It works in the EU normally, paired to your Mac Hub. So an EU iPhone owner who wants a personal-context assistant has, right now, a straightforward option: the Mac does the work, the iPhone is the window. On the Mac, where EU users do get Siri AI, Ostler simply complements it.
Be clear about this too: Siri AI is included with your Apple devices at no extra charge, and it is there with zero setup. That is a real advantage and we are not going to dress it up. Ostler is a paid product – $99 once for the Hub, which is yours to keep, plus $9.99/month for Ostler Pro.
What the money buys is not a smarter chatbot. It is the local-custody layer: an owned, browsable, exportable record of your life that is answered on your own hardware and is architecturally incapable of leaking, alongside the assistant Apple already gives you.
Local · Private · Yours