Sleep data from every wearable, in one schema

What sleep looks like through one API

Sleep is the metric developers most often assume is standardised and most often discover is not. Every provider reports a duration, a set of stages and some efficiency figure, but almost nothing about how those numbers are produced is shared between them. Two devices on the same person on the same night routinely disagree by 30–50 minutes of total sleep time and by considerably more on individual stages.

WearLink normalises the parts that can honestly be normalised — session boundaries, total and per-stage durations in seconds, efficiency as a percentage, and the timestamps that anchor a session to a calendar date — and leaves the provider-specific scores alongside rather than pretending they are interchangeable. You get one object shape whether the night came from an Oura ring, a WHOOP band or an Eight Sleep mattress.

The hard part is not parsing sleep; it is deciding which night a session belongs to and knowing when a provider has silently revised it. Both are handled below the API surface, so your code sees a single settled record per session and a webhook when one changes.

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.

Providers that supply sleep

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.

Webhook events for sleep

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 Event names below are generated from the backend enum, so they cannot drift out of date relative to the API.

Frequently asked questions

Which wearables can WearLink pull sleep data from?

Sleep is mapped for Oura, WHOOP, Fitbit, Withings, Garmin, Polar, Suunto, Ultrahuman and Eight Sleep on the cloud side, plus Apple Health, Health Connect and Samsung Health via the mobile SDKs. Provider connection status varies — the table on this page shows what is connectable today.

Are sleep stages comparable between Oura and WHOOP?

Durations are comparable in the sense that both report seconds in each stage, but the underlying classifiers differ and will disagree on the same night. Treat cross-device stage comparisons as directional, not equivalent. Within a single user on a single device, trends are reliable.

How do I get notified when new sleep data arrives?

Subscribe to the sleep.created webhook event. WearLink delivers the full normalised session in the payload, so you do not need a follow-up API call, and re-delivers when a provider revises a night.

Can I get breathing and respiratory data with sleep?

Yes — series.respiratory_rate.created, series.sleeping_breathing_disturbances.created and series.breathing_disturbance_index.created carry the higher-resolution respiratory streams where the device supports them.