OpenStrap

open firmware · on-device · no subscription

Your recovery data,
finally rented yours.

OpenStrap turns the strap you already own — or your Apple Watch — into a private recovery, strain and sleep coach. Computed on your iPhone, owned entirely by you. No subscription, no cloud lock-in.

Get the app Join the beta

no account to start / works offline / your data stays on-device

  • $60 a year · no sub
  • 100% on your device
  • 24/7 recovery & strain
  • export your data, anytime

no new hardware to buy

Works with what you already wear.

Smart rings, fitness bands, the Apple Watch, or the strap you already own — OpenStrap auto-detects your device on pairing and adapts to whatever it can measure. Our own OpenStrap band, with open firmware, is on the way.

Smart rings Fitness bands Apple Watch The strap you already own OpenStrap band · soon auto-detected on pairing

two ways to track recovery

Stop renting access to your own body.

The usual deal: an open-ended monthly fee, and your most personal data on someone else’s servers. OpenStrap flips it — the scores you rely on, computed on your phone, kept yours.

the subscription way

  • A monthly fee just to read your own body
  • Your data lives on someone else’s servers
  • Cancel, and the insights vanish with it
  • One ecosystem, one locked-in app

the openstrap way

  • $60 a year flat — no monthly subscription, ever
  • Every metric computed on your iPhone
  • Your history is yours — export it anytime
  • Works with rings, bands, Apple Watch & the strap you own

everything the membership gives you

The full picture, without the bill.

Recovery, strain, sleep and the trends underneath them — real screens from the app, every number computed on your phone from your own signals.

recovery

Know when to push, and when to rest.

A single 0–100 readiness score from overnight HRV, resting heart rate and sleep — with the HRV and RHR that drove it, right under the ring.

  • Green, yellow or red band at a glance
  • Built from your own overnight baseline
  • A plain-language call on today’s effort

sleep & sleep need

Every stage of your night, scored.

Automatic staging — deep, REM, light and awake — drawn as a real hypnogram, with efficiency and a personalised sleep-need target based on your recent strain and debt.

  • Deep / REM / light / awake breakdown
  • Sleep efficiency & time in bed
  • Tonight’s need, and how much debt you repaid

day strain

Match today’s training to today’s body.

Cardiovascular load builds continuously from your heart-rate zones across the whole day — every workout and walk — so you can aim for the right effort, not just any effort.

  • Live day-strain from real HR zones
  • Minutes in each of five zones
  • Average and peak heart rate for the day

trends & health monitor

Catch illness and overtraining early.

HRV, resting HR, respiration, SpO₂ and skin temperature each track against your own rolling baseline. When several drift together, the health monitor flags it — before you feel it.

  • Multi-week recovery & HRV history
  • Per-signal baseline deviation
  • Early illness & overtraining warnings

how it works

From strap to insight in three steps.

1

Pair your device

Connect your strap over Bluetooth, or grant Apple Health access for your Apple Watch. No account, no subscription, no setup wizard.

2

We compute locally

Recovery, strain, sleep and stress are calculated right on your iPhone — your raw signals never have to leave the device.

3

See trends & back up

Watch your baselines build over time. Sign in to back up to your own private cloud account and restore on a new phone.

privacy is the default

Your data never has to leave your phone.

Every metric is computed on your iPhone — there’s no third-party analytics pipeline in the middle. Cloud backup is optional, tied to your own account, and built so you can export everything and restore on a new device whenever you want.

open firmware

A band you can actually reprogram.

The OpenStrap band — $149.99, yours to keep — runs open-source firmware. Flash your own builds over the air, against a documented pinout, so you’re never locked into one company’s gear. No rented hardware, no black box on your wrist. Today the app already works with the rings, bands and watches you already have.

Firmware on GitHub
open firmware OTA updates documented pinout

simple pricing

One flat yearly price. Not a subscription.

The going rate for this is a subscription that never ends. The OpenStrap app is $60 a year — one flat price, no monthly fee, no data lock-in. It works today with the rings, bands and watches you already have. (Want the hackable hardware too? The OpenStrap band is $149.99.)

Founding beta · price locks in

Membership

$360 $60/ year

Everything in the app, one flat yearly price — versus the ~$360/yr the usual subscription costs. No monthly fee, no data lock-in. Works today with the devices you already have.

  • Recovery, strain & sleep
  • HRV, RHR, SpO₂ & temp trends
  • Illness & overtraining alerts
  • On-device, private by default
  • Your data, exportable anytime
Join the beta

Founding-beta price locks in for as long as you stay.

Premium · optional

Soon

Optional add-on, layered on top of the $60/yr core — the membership already includes everything above.

  • Predictive illness & recovery forecasting
  • Advanced multi-week trend models
  • Training-load planning
  • Priority new-device support

before you ask

Questions, answered.

Do I need a subscription?

No monthly subscription. The OpenStrap app is one flat $60 a year — not a treadmill that owns your data. Everything is computed on your iPhone, and you can join the beta now.

Can I run my own firmware on the band?

Yes. The OpenStrap band ($149.99) ships with open-source firmware — flash your own builds over the air against a documented pinout, so you actually own and can reprogram the device on your wrist. The app itself is a paid product, and we don’t publish the hardware schematics or Gerber files.

Which devices does it work with?

As many as possible: smart rings, fitness bands, the Apple Watch (via Apple Health), and the popular fitness straps you may already own — with our own OpenStrap band on the way. The app auto-detects your device on pairing and shows only the metrics it can reliably produce.

Is my data private?

Yes. Your biometric data is computed and stored on your iPhone first. Cloud backup is optional and tied to your own account — your data is yours, and you can export it at any time.

Does it work with Apple Watch?

Yes. OpenStrap reads heart rate and beat-to-beat intervals from Apple Health and runs the same recovery, strain and sleep engine it uses for the strap.

How accurate is it?

The analytics are built on published, research-backed methods — Cole–Kripke sleep staging, TRIMP strain and HRV-based recovery — and validated against real device captures. It is a fitness and wellness tool, not a medical device.

join the founding beta

Own your recovery.

$60 a year for the app — no subscription, no data lock-in. Bring the ring, band or strap you already have — drop your email and we’ll send you a beta invite.

Or grab it now on TestFlight.

Not affiliated with any strap manufacturer. For wellness and fitness use — not a medical device.