Wearable APIs: Fitbit, Garmin, Oura and Withings
The four vendor APIs compared as of October 2026 — access rules, memberships, data — the health-store alternative, and one FHIR format for every device.
Fitbit, Garmin, Oura and Withings each run their own cloud API for the data their devices collect, with different access rules: Fitbit is moving to the Google Health API, Garmin's Health API is for approved businesses, Oura's API v2 needs an OAuth app and, for newer rings, an active membership, and Withings' Public API is open to any developer. All four also write to the phone's health store, so a mobile app can read them through Apple HealthKit or Android Health Connect instead. This page compares the options as of October 2026 and shows how to keep the data in one standard format.
| Fitbit | Garmin | Oura | Withings | |
|---|---|---|---|---|
| Cloud REST API | Google Health API | Health & Activity APIs | API v2 | Public API |
| Who can get access | after Google's restricted-scope review | approved businesses | any developer, OAuth app | any developer, no contract |
| Users need a subscription | — | — | Gen3+: Oura Membership | — |
| Also reaches Health Connect / HealthKit | ✓ | ✓ | ✓ | ✓ |
Check each vendor's current terms; they change. Sources: Google, Garmin, Oura and Withings developer and support pages, October 2026.
Each vendor in short
Fitbit. The legacy Fitbit Web API is turned off on 30 October 2026. The successor, the Google Health API, uses Google OAuth 2.0 and restricted scopes that require a privacy and security review. See Fitbit Web API shutdown.
Garmin. The Garmin Connect Developer Program offers a Health API (all-day summaries such as heart rate, sleep and steps), an Activity API (over 30 activity types), a Women's Health API, and Training and Courses APIs. Access is granted to approved businesses; check Garmin's developer site for the current status of new applications.
Oura. Oura API v2 needs an Oura account and an API application created in Oura's developer portal. Oura states that users of Gen3 and later rings without an active Oura Membership cannot access their data through the API; everyone can still download their data files.
Withings. The Public API needs no contract: create an app in the Withings developer dashboard and use OAuth 2.0 (access tokens last 3 hours, refresh tokens a year and rotate). Measurements (weight, blood pressure, heart rate, SpO₂, ECG-related values), activity and sleep are available, with notifications to your server when new data arrives. A demo mode lets you test without a device.
Cloud API or health store?
| Vendor cloud APIs | Phone health store (HealthKit, Health Connect) | |
|---|---|---|
| Integrations to build | One per vendor | One per platform (iOS, Android) |
| Access | Vendor approval, contracts or memberships vary | The person's permission in your app |
| Works without your mobile app | Yes | No |
| Data detail | Vendor-specific, sometimes richer | Standard types, sometimes summarised |
Many teams combine them: the phone's health store for broad coverage, one or two vendor APIs where they need extra detail.
One format for every vendor
Whatever the source, store each reading once as a LOINC-coded FHIR R4 Observation with its source recorded in provenance: steps 41950-7, heart rate 8867-4, resting heart rate 40443-4, HRV 80404-7, SpO₂ 59408-5, sleep 93832-4, weight 29463-7, blood pressure 85354-9. Your dashboards, analytics and AI features then read one model, and a vendor's API change stays in one adapter.
Frequently asked questions
Which wearable API is the easiest to start with?
Withings' Public API needs no contract and has a demo mode. Oura needs an OAuth app; Garmin requires business approval; Fitbit integrations must now use the Google Health API.
Do I need a membership to use the Oura API?
Users of Gen3 and later Oura rings need an active Oura Membership for their data to be available through the API, according to Oura's support documentation.
Is the Garmin Health API free?
Garmin describes the Connect Developer Program as free for approved business developers; some data, such as enhanced beat-to-beat intervals for commercial use, may require a licence fee. Check Garmin's current terms.
Can I get all wearables through one API?
Through the phone, yes: Apple HealthKit on iPhone and Health Connect on Android aggregate data from many devices. Third-party aggregators also exist. Anpheros does not connect to vendor clouds; it stores the data your app collects, in FHIR, with the person's consent.