Ultrahuman API: Ring Data, CGM and Recovery Metrics

Open Wearables Team · May 5, 2026 · 6 min read

Key Takeaways

Ultrahuman Ring AIR provides Recovery Score, Sleep Score, Movement Index, HRV, resting heart rate, skin temperature deviation and nightly blood oxygen.
Ultrahuman's optional CGM (M1 patch) adds continuous blood glucose data, making it the only consumer wearable ecosystem that combines ring biometrics with glucose monitoring in a single API.
The Ultrahuman API is a REST API with OAuth 2.0 authentication. Access requires applying to the developer program, as credentials are not self-serve.
Skin temperature deviation from personal baseline is a nightly metric that provides recovery and illness onset signals comparable to Oura's temperature feature.
Open Wearables normalizes Ultrahuman data alongside other supported providers and preserves CGM glucose data in the normalized output.

Introduction

Ultrahuman is a metabolic health platform built around the Ring AIR wearable and an optional continuous glucose monitor (CGM) called the M1. The combination is unusual in the consumer wearable market: most wearables focus either on fitness performance or sleep quality, while Ultrahuman's design positions metabolic health (how the body processes food and regulates blood sugar) alongside recovery metrics.

The ring form factor captures data during sleep with high accuracy because rings stay on during the night more reliably than wrist devices. Ultrahuman Ring AIR measures HRV, heart rate, skin temperature, SpO2 and movement. The CGM patch, worn on the arm for up to 14 days, measures interstitial glucose continuously throughout the day and night.

For developers, Ultrahuman's combination of ring biometrics and optional glucose data represents a dataset with no equivalent in other consumer wearable APIs. Building features that correlate meal timing, glucose response and overnight recovery is only possible if you have access to both data streams, and Ultrahuman is the only platform that provides both through a single integration.

What the Ultrahuman API Provides

Daily recovery data includes the Recovery Score (0-100 composite based on HRV, resting heart rate and sleep quality), resting heart rate, HRV (rMSSD), cardiovascular load from the previous day's activity and sleep metrics including total sleep duration, sleep efficiency and time in each sleep stage.

Sleep data covers total sleep duration, sleep onset time, wake time, time in light, deep and REM sleep, sleep efficiency percentage, number of wake events, Sleep Score, heart rate during sleep, HRV during sleep and breathing rate during sleep. Sleep temperature deviation is reported as a delta from the user's personal baseline, derived from multiple weeks of nightly measurements.

Movement data tracks steps, active calories, inactive periods (described as Workout Index and Movement Index in Ultrahuman's terminology), and periods of inactivity that the app flags as sedentary time to address.

Glucose data from the M1 CGM patch is available for users who have used or are using the CGM. The data includes timestamped glucose readings at approximately five-minute intervals (in mg/dL or mmol/L depending on the user's regional setting), glucose variability metrics and Ultrahuman's proprietary metabolic score derived from meal response patterns.

Developer Program and API Access

Ultrahuman API access is not self-serve. You must apply to the developer program through Ultrahuman's developer documentation or partnership channel. The application requires information about your use case, user base and how you intend to use the data.

Approval timelines are not publicly specified. Applications for legitimate health and wellness use cases have been processed within one to two weeks in practice. Contact Ultrahuman directly if your application is time-sensitive.

Ultrahuman uses OAuth 2.0 with the authorization code flow. Once a user authorizes your application, you receive an access token and a refresh token. Access tokens expire and must be refreshed using the refresh token. Ultrahuman refresh tokens rotate on use: each time you exchange a refresh token for a new access token, you receive a new refresh token. Store the latest refresh token and discard the previous one after each exchange.

Skin Temperature Data

Ultrahuman's nightly skin temperature is reported as a deviation from the user's personal baseline rather than an absolute temperature in degrees. The baseline is established over the first two to three weeks of ring usage by averaging nightly temperatures. Deviations are expressed as positive or negative deltas.

A consistently positive deviation of half a degree or more above baseline can indicate elevated physiological stress from illness, overtraining or hormonal cycle phase (for female users, temperature rises during the luteal phase are normal and expected). A consistently negative deviation may indicate caloric restriction or cold environment effects.

For product purposes, surface temperature deviation as a trend signal in combination with Recovery Score. A user with a declining Recovery Score and elevated temperature deviation has a stronger case for a rest day than a user with a low Recovery Score and neutral temperature.

Glucose Data in a Biometric Context

CGM data from Ultrahuman's M1 patch is available as a time series of glucose readings. The patch is worn for up to 14 days. After the patch expires, glucose data stops until the user applies a new patch. Not all Ultrahuman users use the CGM; it is a separate purchase from the ring.

When glucose data is available, it enables correlations that ring data alone cannot support. High post-meal glucose spikes are associated with disrupted sleep in research literature. Users who experience nocturnal glucose dips may have worse sleep quality and worse Recovery Scores. These correlations are observable in the data when you have both glucose time series and overnight biometric data for the same user.

Handle CGM data as an optional enhancement in your data pipeline. Design your schema to accept glucose time series when available without breaking features that depend only on ring data. Gate glucose-specific product features on a check for available CGM data in the user's history.

Open Wearables and Ultrahuman

Open Wearables handles Ultrahuman OAuth token management including rotating refresh token handling, developer program credentials, and data normalization. Ring biometric data is mapped to the common schema shared across all providers. CGM glucose data is preserved as a provider-specific extension in the normalized output.

For health apps targeting metabolic health, Ultrahuman support through Open Wearables provides the only consumer wearable integration that delivers both recovery biometrics and continuous glucose data through a single normalized pipeline. Self-hosted, MIT licensed, no per-user fees.

FAQ

Is CGM data available for all Ultrahuman users?

No. The M1 CGM patch is a separate product from the Ring AIR. Users must purchase and use the CGM patch to generate glucose data. When building features that depend on glucose data, always check for data availability before attempting to display glucose-based features.

How accurate is Ultrahuman's sleep staging compared to polysomnography?

Consumer wearable sleep staging uses heart rate, HRV, movement and skin temperature to infer sleep stages. It is meaningfully less accurate than clinical polysomnography. Ring-based devices generally outperform wrist-based devices for sleep metrics because the ring remains stationary during sleep more reliably. For product purposes, treat sleep stage data as directionally accurate trend data rather than clinical-grade measurements.

What happens when a user's CGM patch expires?

When a CGM patch expires, glucose readings stop. The API will not return glucose data for dates after the patch expiry until a new patch is activated. Handle this gracefully by detecting gaps in glucose data and updating your UI to reflect that metabolic monitoring is temporarily unavailable rather than displaying an error.

Does Ultrahuman API provide workout data?

Ultrahuman Ring AIR is not primarily a workout tracker. The ring does not have GPS. Workout data in the Ultrahuman app is primarily heart-rate-based session tracking rather than the detailed training metrics available from Garmin or Polar. If your application needs detailed workout data, plan to pair Ultrahuman with a separate workout provider in your multi-provider architecture.