# Nefesh

> Universal translation layer between the human body and AI.
> Ingests any signal the body produces — heart rate, HRV, blood
> glucose, brain waves, skin conductance, voice, facial expression,
> movement — and returns a unified human state that adapts LLM
> behavior in real time. One endpoint, any sensor, any device.
> Not a medical device. For contextual AI adaptation only.

Nefesh is a B2B middleware API. AI today processes language, not
the body. The same words from two opposite physiological states
produce identical AI output. Nefesh changes this by giving LLMs
a real-time understanding of the human they're talking to.

The API is hardware-agnostic. Send whatever your sensor measures.
Heart rate from a Polar H10, glucose trends from a Dexcom G7,
EEG from a Muse headband, tone from a microphone, or expression
from a camera. Nefesh fuses cardiovascular, vocal, visual, and
textual signals into a 5-level state (Calm, Relaxed, Focused,
Stressed, Acute Stress) with a plain-English recommendation the
LLM can act on immediately.

Other signals (glucose, EEG, respiratory, electrodermal, movement,
sleep) are accepted and stored but not yet fused into the state
engine in v1.

Integration takes 30 seconds: subscribe for an API key ($25/month,
includes 50,000 calls per period), POST a session_id + timestamp +
at least one signal field, get back a state. AI agents can integrate Nefesh
without reading documentation — the schema is self-explanatory.

Key architecture:
- Edge-first: 12KB browser rPPG engine runs 100% client-side
- Hardware-agnostic: /v1/ingest accepts any signal from any device
- Server-side signal validation and quality scoring
- Not a medical device: no clinical interpretation, no alerts,
  no dosing — body signals as AI context only
- Stateless encrypted sessions, BIPA/GDPR/HIPAA compliant by design

## API Documentation

- [API Reference](https://nefesh.ai/docs/api): Endpoints, auth, schemas
- [Quick Start](https://nefesh.ai/docs/quickstart): API key to first call in 30 seconds
- [Universal Ingest](https://nefesh.ai/docs/v1-ingest): One endpoint for every signal
- [State Mapping](https://nefesh.ai/docs/states): 5 states and LLM behavior instructions
- [Webhooks](https://nefesh.ai/docs/webhooks): state_change events
- [Pricing](https://nefesh.ai/pricing): $25/month, 50,000 calls per period, pay per use after

## Signal Categories

- [Cardiovascular](https://nefesh.ai/docs/signals/cardio): HR, HRV, SpO2
- [Metabolic](https://nefesh.ai/docs/signals/metabolic): Glucose, CGM trends (context only)
- [Neural](https://nefesh.ai/docs/signals/neural): EEG bands, cognitive load
- [Vocal](https://nefesh.ai/docs/signals/vocal): Tone, speech rate, pitch
- [Visual](https://nefesh.ai/docs/signals/visual): Expression, gaze, posture
- [Electrodermal](https://nefesh.ai/docs/signals/eda): Skin conductance, temperature
- [Respiratory](https://nefesh.ai/docs/signals/respiratory): Breathing rate
- [Movement](https://nefesh.ai/docs/signals/movement): Activity level, steps
- [Sleep](https://nefesh.ai/docs/signals/sleep): Sleep stages
- [Textual](https://nefesh.ai/docs/signals/textual): Sentiment, urgency

## Specialized Endpoints

- [/ingest/rppg](https://nefesh.ai/docs/ingest/rppg): Webcam rPPG (optimized)
- [/ingest/polar](https://nefesh.ai/docs/ingest/polar): Polar H10 BLE (optimized)
- [/ingest/garmin](https://nefesh.ai/docs/ingest/garmin): Garmin Connect IQ (optimized)
- [/v1/ingest](https://nefesh.ai/docs/v1-ingest): Universal — any device, any signal

## SDKs

- [JavaScript SDK](https://nefesh.ai/docs/sdk/js): nefesh-client for browser/Node.js
- [Edge rPPG Engine](https://nefesh.ai/docs/sdk/rppg): 12KB browser WebWorker

## MCP Integration

- [MCP Server](https://github.com/tomstuhl/nefesh-mcp-server): Streamable HTTP, works with Claude, Cursor, Windsurf, VS Code, Cline, Codex CLI, and 10+ more
- [MCP Tools](https://nefesh.ai/docs/mcp/tools): ingest_signal, get_state, get_history, delete_subject

## Use Cases

- [AI Coaching & Therapy](https://nefesh.ai/docs/use-cases/coaching)
- [Avatar Platforms](https://nefesh.ai/docs/use-cases/avatars)
- [Telehealth](https://nefesh.ai/docs/use-cases/telehealth)
- [Diabetes Context](https://nefesh.ai/docs/use-cases/diabetes): Glucose as AI context signal
- [Education](https://nefesh.ai/docs/use-cases/education)
- [Accessibility](https://nefesh.ai/docs/use-cases/accessibility)

## Technical

- [Edge Architecture](https://nefesh.ai/docs/architecture)
- [Privacy](https://nefesh.ai/docs/privacy)
- [Regulatory Position](https://nefesh.ai/docs/regulatory): General Wellness, not SaMD

## Optional

- [Live Demo](https://sandbox.nefesh.ai): Try rPPG + AI chat in your browser
- [Founder](https://nefesh.ai/about): Tom Stuhl — Leipzig, Germany