Introduction
Circadify is a platform for measuring vital signs from a standard device camera — no wearables, no contact sensors. Using remote photoplethysmography (rPPG) and on-device face analysis, the SDK captures physiological signals from subtle changes in skin color that are invisible to the naked eye.
What You Can Measure
Section titled “What You Can Measure”A single 30-second scan from a smartphone or laptop camera returns:
| Vital Sign | Unit | Description |
|---|---|---|
| Heart Rate | BPM | Real-time pulse rate extracted from facial blood flow signals |
| Heart Rate Variability | ms | RMSSD derived from inter-beat interval analysis |
| Respiratory Rate | breaths/min | Breathing rate derived from periodic variations in the PPG signal |
| Blood Oxygen (SpO2) | % | Blood oxygen saturation estimated from multi-wavelength skin reflectance |
| Systolic Blood Pressure | mmHg | Peak arterial pressure during heartbeat |
| Diastolic Blood Pressure | mmHg | Resting arterial pressure between heartbeats |
Each result includes a confidence score (0–1) indicating measurement reliability.
How It Works
Section titled “How It Works”-
On-device preprocessing — The Circadify Vision Engine runs in the browser via WebAssembly. It detects the face, extracts skin regions, and encodes them into a compact format. Raw camera frames never leave the device.
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Local capture — Over ~24 seconds at 30 FPS, the SDK captures and preprocesses frames into a structured binary payload. No photos, video, or identifiable images are transmitted.
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Encrypted upload — The preprocessed data is uploaded directly to secure cloud storage over TLS 1.3.
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Server-side inference — Proprietary ML models process the data to extract heart rate, respiratory rate, HRV, blood pressure, and SpO2.
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Results returned — Vital signs with confidence scores are returned directly in the API response. No health data is stored server-side.
Integration Options
Section titled “Integration Options”- Web SDK (
@circadify/sdk) — Drop-in JavaScript/TypeScript library with optional built-in scanning UI. Works in Chrome 80+, Firefox 75+, Safari 14+, and Edge 80+. - REST API — Server-side endpoints for session management, result retrieval, and account operations. Authenticate with API keys.
- React components — Pre-built
CircadifyProviderandCircadifyScancomponents with hooks. - Headless mode — Full SDK capabilities without any UI, for custom implementations.
Developer Portal
Section titled “Developer Portal”Create your account and manage everything at developer.circadify.com:
- Create and revoke API keys
- Test keys and run live scans
- Monitor usage and scan quotas
- Manage billing and upgrade plans
| Plan | Monthly Scans | Rate Limit | API Keys | Price |
|---|---|---|---|---|
| Starter | 500 | 300 req/hr | 3 | $49/mo |
| Pro | 5,000 | 1,000 req/hr | 5 | $399/mo |
| Enterprise | 50,000 | 5,000 req/hr | 10 | Custom |
Next Steps
Section titled “Next Steps”- Quick Start — Create an account, get a key, and run your first scan
- Authentication — API key types, usage, and security
- Web SDK Installation — Install and configure the browser SDK
- REST API Overview — Server-side endpoints and authentication