Blood Pressure data from every wearable, in one schema
Systolic and diastolic readings from connected cuffs, with the measurement context that makes them interpretable.
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Providers connectable today
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Webhook events in this family
millimetres of mercury (mmHg)
Canonical units
What blood pressure looks like through one API
Blood pressure is the one metric in this catalog that comes almost entirely from a regulated medical device rather than a fitness wearable. Connected cuffs are cleared instruments, and the readings they produce are clinical measurements rather than proprietary estimates — which makes them more trustworthy than most wearable data and considerably more consequential to handle badly.
WearLink normalises systolic and diastolic to mmHg and emits them both as a paired summary object and as separate series, because products chart them separately far more often than together. Pulse rate captured at the moment of measurement travels with the reading rather than being merged into the general heart-rate stream, since a cuff reading and a continuous optical reading are not the same kind of observation.
Readings are episodic by nature — a user measures when prompted or when they remember — so the API returns what exists rather than manufacturing a daily series. Any smoothing or trend line is a product decision that belongs to you.
Where providers disagree
The part that costs you weeks if you build this yourself. None of the following is a WearLink limitation — it is how the underlying providers actually behave.
Measurement context changes the number more than physiology does
Posture, cuff placement, arm height, recent caffeine and simply having just walked upstairs move a reading by clinically meaningful amounts. A cuff cannot tell you whether the user followed the protocol. Single readings are noisy in a way that is invisible in the payload; clinical practice averages multiple readings for a reason.
Manual entries are mixed in with device readings
Apple Health and Health Connect accept hand-typed blood pressure alongside device-written values, and the two arrive in the same stream. A typed value may be transcribed from a clinic visit weeks earlier. Use the source attribution to separate them before doing anything that assumes recency.
The thresholds you display are a regulatory decision
Categorising a reading as normal, elevated or hypertensive means applying a guideline, and guidelines differ between jurisdictions and have changed over time. Rendering a category — rather than a number — moves your product closer to making a medical claim. Decide that deliberately rather than by copying a colour scale.
Cuffs are shared between household members
Like scales, a home blood pressure monitor is often used by more than one person, and attribution to the wrong profile is common. Implausible jumps in a user history are frequently a different person rather than a clinical event.
Providers that supply blood pressure
Status is read from the same provider table the rest of the site uses, so nothing here can claim a provider is connectable when it is not. Coverage also varies by hardware generation within a brand.
| Provider | Category | Status |
|---|---|---|
| Withings | Cloud OAuth | Live |
| Apple Health | Mobile SDK | Mobile SDK |
| Google Health Connect | Mobile SDK | Mobile SDK |
| Samsung Health | Mobile SDK | Mobile SDK |
Webhook events for blood pressure
Subscribe to the summary event for settled records, and to the series streams when you need the underlying samples. Event names below are generated from the backend enum, so they cannot drift out of date relative to the API.
Summary object
blood_pressure.created
Series streams
series.blood_pressure_systolic.createdseries.blood_pressure_diastolic.createdFrequently asked questions
- Which blood pressure devices work with WearLink?
- Withings on the cloud side, plus any cuff that writes into Apple Health, Health Connect or Samsung Health — which covers most consumer connected monitors indirectly.
- Does WearLink return systolic and diastolic separately?
- Both — as a paired summary object and as two independent series, so you can chart them separately without unpacking a combined record.
- Can I show users a hypertension classification?
- Technically yes, but doing so applies a clinical guideline and moves your product toward a medical claim. The guidelines differ by jurisdiction. Treat that as a deliberate regulatory decision, not a display detail.
- Is a home cuff reading as reliable as a clinic reading?
- The instrument usually is; the conditions are not. Posture, timing and recent activity introduce more variation than the device itself. Averaging several readings is the standard mitigation.
Related data types
15 normalised data families in total — see them all or browse integrations by provider.