The strap measures you all day; the question is what other software is allowed to see. People arrive at this question from every direction — a coach who wants the data, a training app, a spreadsheet habit — and the answer is more organized than the forum threads suggest. There are three official doors, and each carries different cargo.
Door one: the developer API — your summaries, by permission
WHOOP publishes an official API for developers. It works by consent: you authorize an app through OAuth, and it can then read your summary data — recovery (including HRV and resting heart rate), sleep, daily strain cycles, workouts, and basic profile information. This is the door for coaching platforms and dashboards that want your trends.
What it does not carry is the raw feed. The API serves the computed summaries, not the continuous heart-rate stream the strap records all day. An app on this door sees your day the way the Whoop app summarizes it.
Door two: Apple Health — summaries again, thinner
The Apple Health integration syncs workouts, sleep sessions, and once-daily summary values — resting heart rate, respiratory rate, blood oxygen. For sleep and workout data flowing to other iOS apps, it does the job.
For cardiac data it is thinner than people expect: independent testing of the integration found Whoop writes one heart-rate value per day to Apple Health and excludes HRV entirely. The full accounting is in our article on what Whoop syncs to Apple Health.
Door three: Heart Rate Broadcast — the live signal itself
The third door is different in kind. Heart Rate Broadcast streams the strap’s live heart rate over the standard Bluetooth heart-rate profile — the same open protocol a chest strap uses. Any device or app built to read a chest strap can read it: gym equipment, bike computers, training apps. It is the only door that carries the continuous signal, and it is live-only — a real-time stream with no backfilling, in WHOOP’s own words.
What about the unofficial routes?
The community has built remarkable things against Whoop’s private protocol — reverse-engineered clients, exporters, full replacement stacks. They exist because people want their data, and they demonstrate real skill. They also ride an unsanctioned channel that can shift under them with any firmware release. The broadcast is the sanctioned path to the live signal: supported and documented — the protocol doesn’t move, even when the toggle needs re-checking after an update.
Which door do you want?
Trends and history for a coach or dashboard: the API. Sleep and workouts flowing to iOS apps: Apple Health. The live, continuous signal, as it happens: the broadcast. brainful — the b-score app for Whoop straps — is built entirely on that third door: it listens to the broadcast and scores each calendar event 0–100 (the b-score) — what each hour was actually worth — on the phone, and nothing leaves the phone. Whichever door fits your case, the useful step is the same: know what each one carries before you blame the app on the other side of it.
Sources: WHOOP for Developers (developer.whoop.com) — the OAuth model and summary resources; DC Rainmaker, “Whoop Exporting to Apple Health: Here’s how it actually works” (2022) — the per-day heart-rate finding and HRV exclusion; WHOOP Support, “Heart Rate Broadcast.” Integration details can change with app updates.