> ## Documentation Index
> Fetch the complete documentation index at: https://developer.neurofit.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Neurofit Vitals SDK: On-Device HRV & Health Metrics

> Add clinical-grade heart rate, HRV, and respiration measurements to your iOS or Android app with a 60-second finger scan. No wearable required.

The Neurofit Vitals SDK lets you embed precision biometric readings directly into your wellness app. Your users hold their fingertip over the phone's rear camera for 60 seconds and receive validated measurements for heart rate, HRV (RMSSD and SDNN), breathing rate, and more — all processed entirely on-device.

<CardGroup cols={2}>
  <Card title="How It Works" icon="camera" href="/how-it-works">
    Learn how the finger-scan technique delivers chest-strap accuracy without a wearable
  </Card>

  <Card title="Quickstart" icon="rocket" href="/getting-started/quickstart">
    Integrate the SDK into your app in minutes
  </Card>

  <Card title="iOS Integration" icon="apple" href="/guides/ios-integration">
    Step-by-step guide for Swift integration
  </Card>

  <Card title="Android Integration" icon="android" href="/guides/android-integration">
    Step-by-step guide for Kotlin integration
  </Card>

  <Card title="Metrics Reference" icon="heart-pulse" href="/metrics/overview">
    Explore every metric the SDK measures and what it means
  </Card>

  <Card title="Validation Data" icon="chart-line" href="/validation">
    See accuracy benchmarks from the clinical validation study
  </Card>
</CardGroup>

## Why the Vitals SDK?

The Vitals SDK is the same measurement engine that powers the NEUROFIT app's Vitals feature, packaged for third-party developers. It is validated against a Polar H10 chest strap across 30 participants and 265 readings.

<CardGroup cols={3}>
  <Card title="0.47 bpm" icon="heart">
    Mean heart rate error vs. chest strap
  </Card>

  <Card title="3.4 ms" icon="wave-sine">
    Mean HRV (RMSSD) error vs. chest strap
  </Card>

  <Card title="94.7%" icon="circle-check">
    HRV readings within 10 ms of the reference
  </Card>
</CardGroup>

## Get Started in Three Steps

<Steps>
  <Step title="License the SDK">
    Choose a Binary or Source license and receive your SDK license key. [Contact us to get started](/getting-started/licensing).
  </Step>

  <Step title="Install the SDK">
    Add the SDK to your iOS or Android project via Swift Package Manager or Maven. See the [Installation guide](/getting-started/installation).
  </Step>

  <Step title="Run your first scan">
    Configure the SDK with your license key, present the scan UI, and receive results in your delegate or callback. Follow the [Quickstart](/getting-started/quickstart).
  </Step>
</Steps>

## Key Features

* **Fully on-device** — no images stored or transmitted, deterministic signal processing
* **Under 1 MB** footprint, native Swift and Kotlin, runs on \~99% of iPhones and \~97% of Android phones
* **Six metrics per scan** — heart rate, RMSSD, SDNN, Baevsky stress index, Poincaré SD2:SD1, and breathing rate
* **Quality gating** — unreliable readings are withheld automatically with live guidance during each scan
* **Fixed perpetual license** — no per-scan or per-user fees, you own your outcomes data

<Note>
  The Neurofit Vitals SDK is not a medical device and is not intended for the diagnosis, treatment, or prevention of any condition. Always encourage users to consult a healthcare professional for medical decisions.
</Note>


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