Your strap. Your data. Your machine. Local-first, no cloud.
⬇ Download · Features · Protocol · ♥ Support · Contact
Pre-built apps you can run right now:
| Platform | Build | Notes |
|---|---|---|
| macOS | NOOP.app (see Releases) |
Apple Silicon + Intel. Drag to Applications. |
| Android | NOOP-full.apk (see Releases) |
The full app. minSdk 26 (Android 8+). Sideload — enable "install unknown apps". |
| Android (demo) | NOOP-demo.apk |
Preloaded with sample data so you can explore every screen with no strap. Installs alongside the full app. |
| iOS | — | The shared library is iOS-ready; the app is on the roadmap. |
Prefer to build it yourself? See docs/BUILD.md.
Everything runs offline. The only feature that ever uses the network is the optional AI Coach, and only with your own API key.
NOOP is a standalone, fully offline companion app for WHOOP straps (4.0 and 5.0). It pairs directly with the strap over Bluetooth, stores everything on your own device in SQLite, imports your existing WHOOP and Apple Health history, and computes recovery, strain, HRV, and sleep locally, with no WHOOP account and no WHOOP cloud.
It is built on prior open-source reverse-engineering work and exists for one reason: to let someone who owns a WHOOP strap read their own biometric data from their own device, on a machine they control.
Not affiliated with WHOOP. NOOP is an independent, unofficial interoperability project. It is not affiliated with, endorsed by, or connected to WHOOP, Inc. "WHOOP" is used only to identify the hardware NOOP talks to. Use it only with a device you own, and not in breach of any agreement that applies to you. NOOP is not a medical device; every derived metric is an approximation, not clinical data. See
DISCLAIMER.md.
- Why NOOP
- Features
- Platform status
- Architecture
- Quickstart (macOS)
- How your data flows
- Privacy
- Attribution
- Support (optional)
- Disclaimer
- Docs
You bought the strap. The biometric stream it produces is yours. NOOP is built on that premise:
- Own your data. NOOP reads heart rate, R-R intervals, SpO₂, skin temperature, respiration, accelerometer/gravity, battery, and event data straight off the strap over Bluetooth and writes it to a local SQLite database. Nothing is uploaded anywhere.
- Account-free and local. NOOP never logs into a WHOOP account and never hits a WHOOP server. It does not bypass any login, paywall, or DRM; it simply talks to a device you own and reads data you generated.
- Bring your history. Already have years of data in the official app or in
Apple Health? Import the WHOOP CSV export and/or your Apple Health
export.xmlonce, and it's permanently on your machine. - Transparent math. Recovery, strain, HRV, and sleep are recomputed on-device from documented, citable methods (Task Force 1996 HRV, Karvonen %HRR, Edwards / Banister TRIMP, Tanaka HRmax, and so on). The algorithms are approximations of — not reproductions of — any proprietary model, and every analyzer file documents exactly what it does.
The macOS reference app organizes everything behind a single sidebar
(Strand/App/RootView.swift). Each item below is a real screen in
Strand/Screens/.
| Screen | What it does |
|---|---|
| Today (Control Center) | Home dashboard: recovery ring, a "today's synthesis" insight, a grid of stat tiles (recovery, strain, sleep, HRV, RHR, SpO₂, respiratory, steps, weight, calories) each with a 14-day sparkline, recent workouts, and a data-sources footer. |
| Live | Real-time view of the connected strap — heart rate and frame stream as they arrive (~1 Hz). |
| Breathe | HRV haptic breathing biofeedback. The strap both measures HRV (R-R intervals) and buzzes its haptic motor, so NOOP paces your breath with felt cues (one buzz inhale, two exhale) and shows live HR + rolling RMSSD responding as the session deepens. Presets: Relax 4-6, Coherence 5.5, Box 4-4. |
| Intervals | Silent haptic HIIT timer. The strap buzzes every transition (triple-buzz into WORK, single into REST, 3-2-1 tick at phase ends, long buzz on finish) so you train hands-free. Falls back to a glanceable visual timer with no strap. |
| Explore (Metric Explorer) | Interrogate any single metric over time, built from the metric catalog (Strand/Data/MetricCatalog.swift). |
| Compare | Plot two metrics together / against each other over a shared timeline. |
| Insights | Behavioral and correlational insights derived from your own series. |
| Sleep | Sleep sessions with a hypnogram, stage breakdown, efficiency, resting HR, and HRV — computed by the on-device sleep stager. |
| Trends | Long-range trends across recovery, strain, sleep, and biometrics. |
| Workouts | Detected exercise sessions with strain and heart-rate detail. |
| Health | Biometric overview (HR, HRV, SpO₂, skin temperature, respiratory rate, etc.). |
| Stress | Day-level stress / autonomic load visualization. |
| Apple Health | Browse and reconcile data imported from your Apple Health export. |
| Data Sources | One-tap import of a WHOOP CSV export or an Apple Health export, plus live-strap status. "Bring your history in once, then it's yours." |
| Notifications | Configure local notifications and thresholds (Strand/Data/NotificationSettingsStore.swift). |
| Automations | Turn the strap's physical inputs and live biometrics into Mac actions — all on-device (see below). |
| Settings | Profile, preferences, and app configuration. |
| Support | Attribution + optional crypto donations. The whole app works without them. |
There is also a menu-bar extra (Strand/MenuBar/MenuBarContent.swift) with a
glanceable live HR readout and a compact popover, and a first-run onboarding
wizard (Strand/Onboarding/OnboardingWizard.swift).
Strand/Screens/AutomationsView.swift + Strand/System/MacActions.swift:
- Double-tap → Mac action. Double-tap the strap to lock the Mac, buzz back to
confirm, mark a moment, do nothing, or run any macOS Shortcut by name (via
the
shortcuts://URL scheme, so it's sandbox-friendly). - Wear & presence. Lock the Mac (or run a Shortcut) the moment the strap leaves your wrist; run a Shortcut when it goes back on. (macOS reserves true auto-unlock for Apple Watch — NOOP can lock, not unlock.)
- Haptic coaching. HR-zone coaching and an experimental resting-stress nudge — the strap buzzes so you don't have to watch a screen.
- Smart alarm. Arms the strap's own firmware alarm to buzz at your wake time (still fires if the Mac is asleep or NOOP is closed), with an optional light-sleep wake window when the Mac stays awake and connected.
NOOP's logic lives in cross-platform Swift packages, and the same protocol, storage, analytics, and scoring is ported to Kotlin on Android. Both apps pair with the strap and score recovery, strain and sleep on your own device — no import required.
| Platform | Status |
|---|---|
| macOS | ✅ Full app (Strand/, SwiftUI, macOS 13+). Pairs over BLE, offloads the strap's history, and scores recovery / strain / sleep on-device. The complete feature set above runs here. |
| Android | ✅ Full app (android/, Jetpack Compose, Android 8+). Pairs over BLE, persists and scores on-device, and imports WHOOP / Apple Health / Health Connect. Grab the APK from Releases. |
| iOS | 🟡 Libraries ready. Every package declares .iOS(.v16) and UI-framework code is guarded with #if canImport(UIKit) / AppKit; an iOS app target is planned. |
NOOP computes your scores on your own device, so like any recovery wearable it needs a little data before everything fills in:
- Live heart rate shows the moment the strap connects.
- Strain and sleep appear after you've worn it and synced — the strap's last ~14 days offload automatically over the first few minutes.
- Recovery needs a few nights for the app to learn your personal baseline, then sharpens each night. WHOOP makes you wait for the same reason.
- In a hurry? Import your WHOOP export in Data Sources and your full history fills in about a minute.
The repository is split into platform-pure Swift packages plus a macOS app target.
All packages declare both .iOS(.v16) and .macOS(.v13); framework-specific UI is
guarded with #if canImport(UIKit) / #if canImport(AppKit).
Strand/ macOS SwiftUI reference app (this is what you build)
Packages/
WhoopProtocol/ BLE frame parsing, CRC, command/event/packet decode
WhoopStore/ GRDB/SQLite persistence (migrations, streams, caches)
StrandAnalytics/ HRV / recovery / strain / sleep / correlation math
StrandImport/ WHOOP CSV + Apple Health importers
StrandDesign/ SwiftUI design system (palette, components, charts)
Tools/Backfill/ CLI tool for backfilling decoded data
Fixtures/ sample WHOOP export for tests
Platform-pure (no CoreBluetooth import) so it runs in tests and CLI tools unchanged. It decodes the on-wire frame format for both strap generations:
public enum DeviceFamily: String, Sendable, CaseIterable {
case whoop4 // CRC8 (poly 0x07) header check; service 61080001-…
case whoop5 // CRC16-Modbus header check, "puffin" packet types; service fd4b0001-…
}Decoding is schema-driven (Resources/whoop_protocol.json) and includes CRC8,
CRC16-Modbus, and zlib CRC-32 implementations, frame framing, value
interpretation, and historical-stream reassembly. The app layer (Strand/BLE/,
Strand/Collect/) wraps these UUID strings in CBUUID and handles bonding,
offload, and live notifications.
Everything is stored on-device in SQLite (using
GRDB.swift). The schema is a versioned
migrator (Database.swift, currently through v9). Examples of decoded-stream
tables created in v1–v3:
CREATE TABLE hrSample (deviceId TEXT, ts INTEGER, bpm INTEGER, PRIMARY KEY(deviceId, ts));
CREATE TABLE rrInterval (deviceId TEXT, ts INTEGER, rrMs INTEGER, PRIMARY KEY(deviceId, ts, rrMs));
CREATE TABLE spo2Sample (deviceId TEXT, ts INTEGER, red INTEGER, ir INTEGER, PRIMARY KEY(deviceId, ts));
CREATE TABLE skinTempSample(deviceId TEXT, ts INTEGER, raw INTEGER, PRIMARY KEY(deviceId, ts));
CREATE TABLE respSample (deviceId TEXT, ts INTEGER, raw INTEGER, PRIMARY KEY(deviceId, ts));Later migrations add server-derived metric caches (sleepSession, dailyMetric),
cursors, a raw frame outbox, and more.
Pure, database-free analyzers. Each is documented and grounded in published methods (and is explicitly an approximation, not a reproduction of any proprietary model):
| File | Computes |
|---|---|
HRVAnalyzer.swift |
RMSSD + SDNN from R-R intervals (Task Force 1996), with range + Malik ectopic filtering. |
RecoveryScorer.swift |
A 0–100 recovery score: HRV-dominant z-score + logistic composite vs personal baselines. |
StrainScorer.swift |
A 0–21 logarithmic strain scale from %HRR (Karvonen) and Edwards / Banister TRIMP. |
SleepStager.swift |
Sleep/wake detection + approximate 4-class staging from cardiorespiratory + gravity features. |
CorrelationEngine.swift |
Pearson r, OLS regression, day-aligned and lagged correlations between two series. |
WorkoutDetector.swift, Baselines.swift, BehaviorInsights.swift, AnalyticsEngine.swift |
Workout detection, rolling baselines, behavioral insights, and the per-day orchestrator. |
- WHOOP CSV export (
WhoopExportImporter.swift): header-name-driven, tolerant parser forphysiological_cycles.csv,sleeps.csv,workouts.csv, andjournal_entries.csv, from a folder or.zip. The same schema covers WHOOP 4 / 5 / MG. - Apple Health export (
AppleHealthImporter.swift): a streaming SAX parser (XMLParser) forexport.xml(which can exceed 1 GB), with correlation-dedupe, unit normalization (e.g. SpO₂ fraction → %), and sleep-stage mapping.
Palette, typography, motion, and reusable components/charts (RecoveryRing,
StrainGauge, Hypnogram, Sparkline, TrendChart, YearHeatStrip,
StrandCard, StatePill, …) — no external UI dependencies.
Requirements: macOS 13+, Xcode 15+ (Swift 5.9), and a Mac with Bluetooth. To pair live, you need your own WHOOP strap; to just explore, you can import a CSV / Apple Health export instead.
The Xcode project is generated from project.yml with
XcodeGen.
# 1. Clone
git clone <your-fork-url> NOOP
cd NOOP
# 2. (Re)generate the Xcode project from project.yml
brew install xcodegen # if you don't have it
xcodegen generate
# 3. Open and run
open Strand.xcodeproj
# Select the "Strand" scheme → Run (⌘R). The built app is named NOOP.Notes:
- Bundle id
com.noopapp.noop, product name NOOP, sandboxed with the Bluetooth and user-selected-files entitlements. - Swift Package Manager resolves the only third-party dependencies automatically: GRDB.swift (SQLite) and ZIPFoundation (export unzip).
- Run the tests from Xcode (the
StrandTeststarget + each package's test target), or per-package withswift testinsidePackages/<Name>/.
To explore without an Xcode project, the packages build on their own:
cd Packages/WhoopProtocol && swift build && swift testWHOOP strap ──BLE──▶ Strand/BLE + Strand/Collect ──▶ WhoopProtocol (decode)
│
WHOOP CSV ─┐ ▼
Apple Health├─▶ StrandImport (parse) ───────────▶ WhoopStore (local SQLite)
export.xml ─┘ │
▼
StrandAnalytics (recovery/strain/
HRV/sleep, on-device)
│
▼
Strand (SwiftUI) + StrandDesign
Every arrow stays on your machine.
Offline by design. NOOP has no server, no telemetry, and no account. Your strap data, imports, and computed metrics live in a local SQLite database on your device and never leave it.
NOOP stands on open-source reverse-engineering and interoperability work. With thanks:
johnmiddleton12/my-whoop— the WHOOP 4.0 BLE protocol; theWhoopProtocolandWhoopStorepackages and the collection logic are adapted from this work.b-nnett/goose— the WHOOP 5.0 / MG BLE reverse-engineering (thefd4b0001-…service family, CRC16-Modbus header, and "puffin" packet types) that NOOP's WHOOP 5.0 path is ported from.groue/GRDB.swift— SQLite persistence.weichsel/ZIPFoundation— export unzipping.
NOOP contains no WHOOP proprietary code, firmware, logos, or assets, and performs
no DRM circumvention. Full detail in ATTRIBUTION.md.
NOOP is free and always will be, and never gates a feature behind payment. If it's
useful to you and you want to help with the development and testing costs, optional
crypto donation addresses are shown on the in-app Support screen and listed in
docs/DONATIONS.md. Donations are 100% optional and the app
never asks twice.
Contact: questions, feedback, and bug reports → thenoopapp@gmail.com
NOOP is an independent, unofficial, non-commercial interoperability project. It is not affiliated with, endorsed by, or connected to WHOOP, Inc. All references to "WHOOP" are nominative — used only to identify the third-party hardware NOOP interoperates with.
NOOP is not a medical device. Heart rate, HRV, recovery, strain, sleep stages, SpO₂, respiratory rate, and skin temperature are approximations computed from published methods. They are not clinically validated and are not medical advice. Do not use them to diagnose, treat, or make health decisions — consult a qualified professional.
Provided as-is, with no warranty, for personal and educational use. You
use it at your own risk. Read the full notice in DISCLAIMER.md.
DISCLAIMER.md— trademark, interoperability, and medical/legal notice.ATTRIBUTION.md— full credits and licensing notes.docs/DONATIONS.md— optional donation addresses (also in-app under Support).project.yml— XcodeGen project definition (source ofStrand.xcodeproj).