Your health AI that never phones home.
Sirius runs a full medical-grade language model entirely on your device. Voice, documents, Apple Health, calendar — processed locally. No cloud. No servers. No data leaves your iPhone or Mac. Ever.
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Every "private" health app you trust runs on the cloud. And every cloud-based health AI has a leak, a partner, or a buyer waiting.
patients' mental health data shared with Google, Meta & TikTok for ad targeting.
users' menstrual cycle data shared with Facebook, Google & ad networks.
FTC fine for sharing prescription data with third-party advertisers.
FTC settlement for sharing mental health data with Facebook & Snapchat.
The pattern is the model. Cloud-first AI means your health data is the product. Sirius is built on the opposite assumption.
Sirius is an AI health assistant for iPhone and Mac. It understands your lab reports, listens to your questions, reads from Apple Health, and remembers your medical history — all without sending a single byte to any cloud.
It uses an integrated model pipeline — Gemma 4 E2B for the base plan and the stronger Gemma 4 E4B for Pro — running on iPhone and Mac with built-in OCR, speech, a custom Health Memory architecture, and Bluetooth peer sync. No external APIs ever see your health data.
See how Sirius handles voice commands, document scanning, and health insights — all on-device.
1.5B+ active Apple devices. Rising distrust in cloud-based health AI. The wedge for an on-device, privacy-first health companion has never been wider.
Total addressable market across digital health, telemedicine, wearables, and health AI worldwide.
Global mHealth apps market — iOS leads with 52.33% revenue share thanks to device penetration and ecosystem trust.
Defensible niche — privacy-first Apple users who already track health data and distrust cloud-based AI.
Your health data leaves your device, travels to a server, gets processed in the cloud — and you trust their promise not to misuse it. Sirius is the only one where that's physically impossible.
Connects to Apple Health (movement, sleep, activity) and integrates with medical records — all routed to OpenAI's cloud.
Pulls Apple Health, EHR records, plus Fitbit, Ultrahuman and Withings data — every byte processed on Perplexity's servers.
Uses your queries and signals to improve their models. Same trust-the-policy model as everyone else.
All three say “we don't sell your data.” So did Cerebral — before sharing 3.1M patients' data with Meta, Google, and TikTok.
| Feature | ChatGPT Health | Perplexity Health | Apple Health + Siri | Sirius |
|---|---|---|---|---|
| AI processing location | Cloud (OpenAI) | Cloud (Perplexity) | Cloud (Apple) | On-device (Gemma 4) |
| Health data sent to server | Yes | Yes | Yes | Never |
| Persistent health memory | No | No | No | Yes |
| Cross-device sync | Via cloud | Via cloud | Via iCloud | Peer-to-peer (no cloud) |
| Works offline | No | No | Limited | Fully |
| Proactive calendar awareness | No | No | Basic | Yes |
| Document OCR for medical reports | No | No | No | Yes |
| “We won't sell your data” | Promise | Promise | Promise | Architecturally impossible |
Sirius is the only health AI that processes everything on-device. No cloud. No API calls. No servers. Your data physically cannot be leaked, sold, or breached — because it never leaves your iPhone.
Speech, OCR, LLM inference, health memory, and sync — every layer runs locally. No external APIs in the critical path.
We can't sell what we never receive. The ‘no cloud’ promise is enforced by the architecture itself, not a marketing page.
Talk to it like a friend. Point your camera at a report. Open the app — your next appointment is already on the home screen.
Your iPhone and Mac sync your health profile over Bluetooth using a CRDT merge. No account, no server, no internet required.
The complete stack — model, memory, sync, retrieval, and search sanitization — runs on hardware you already own.
medicationsalways injectconditionsalways injectallergiesalways injectconversationssummariessession closelab_resultsappointmentsfetchStructuredContext()semanticSearch(query, topK=5)## Allergies - Penicillin → rash (severe) ## Active Medications - Lisinopril 10mg daily - Metformin 500mg ×2 ## Active Conditions - Hypertension [active] ## Relevant Context [conversation chunks...]
Four ways in. One private, on-device brain. Every input flows into the same Gemma 4 pipeline and the same Health Memory — no upload, no cloud, no compromise.
Speak naturally — Sirius transcribes on-device and replies with a natural voice.
Upload PDFs, Word docs, or images. Sirius parses, summarizes, and remembers them.
Snap a lab report, prescription, or discharge note. VisionKit extracts every value.
Type like you would to a doctor friend. Streaming responses, full markdown.
Sirius reads your calendar on-device, automatically detects doctor and hospital visits, and surfaces a personalized prep brief — grounded in your actual health memory: your conditions, medications, recent labs, and what you asked about last time.
No Reddit threads. No SEO health blogs. No data brokers. When a web search is needed, Sirius queries only these ten verified medical authorities — and the query itself is sanitized and de-identified before it ever leaves your device.
When you ask about a drug, condition, or clinical trial, Sirius strips every personal identifier, rewrites the query into a generic medical question, and sends only that sanitized query through TinyFish to retrieve public information from the trusted sources above. No personal identifiers ever leave your device.
We believe the most personal data a human generates — their body, their conditions, their fears about tomorrow's appointment — should never have to live on someone else's server. Sirius is our proof that intelligent, helpful, deeply personalized health AI can exist entirely on the device in your pocket. No compromises. No exceptions.
The subscription is the business model — so your health data stays yours, by design.
Private health AI on a single device.
The full on-device pipeline. Both devices, deeper memory, smarter model.
Cancel anytime · Student & researcher discounts available
Designed, engineered, and shipped at the O1 Summit Hackathon.
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