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Overview

Polar provides access to exercise, daily activity, sleep, and heart rate data from Polar devices through the AccessLink API. The integration uses OAuth 2.0 for authentication and pull-based syncing to fetch data.

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Supported data types

Data TypeSupport
Workouts / ExercisesYes (with optional HR samples, zones, route)
Sleep (with stages)Available via API - not yet implemented
Daily activityAvailable via API - not yet implemented
Continuous heart rate (5-min intervals)Available via API - not yet implemented
Nightly Recharge / RecoveryAvailable via API - not yet implemented
Open Wearables currently syncs exercise/workout data from Polar. The AccessLink API also exposes sleep, daily activity, continuous HR, and Nightly Recharge data - support for these types is planned for a future release.

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Data delivery

MethodDescription
Polling (pull)Open Wearables periodically fetches exercise data via the Polar AccessLink API (via Celery Beat)
Webhooks: Polar supports webhooks for event notifications, but Open Wearables does not yet implement a Polar webhook handler. Data is synced via periodic polling only. Webhook support is planned for a future release.

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What you need by the end

  • App credentials: Client ID + Client Secret from the Polar AccessLink admin panel
  • Redirect URI registered in your Polar application

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Prerequisites

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Application walkthrough

1

Create a Polar Flow account

If you don’t have one yet, create a free account at flow.polar.com.This is the same account used by Polar device owners - no separate developer account is needed.
2

Register your application at Polar AccessLink

Go to the Polar AccessLink Admin and sign in with your Polar Flow credentials.Click Create client to start the registration process. You’ll go through four tabs:1. Contractual Information
  • Fill in your organization details (name, address, country)
  • Toggle “I intend to integrate on behalf of a client or third-party organization” if applicable
  • Accept the AccessLink Limited License Agreement
2. Application Information
  • Application Name: Your app name (e.g. “Open Wearables”)
  • Business contact (email): Your contact email
  • Description: Brief description of your application
  • Application Web site: Your app’s website (optional)
  • Authorization redirect URL: Your OAuth callback URL - for local development use http://localhost:8000/api/v1/oauth/polar/callback
  • Available data types: Enable all three - Exercise data, Daily activity data, Physical information data
3. Check InformationReview the summary of your organization and application details, then click Confirm.4. CredentialsAfter confirmation, you’ll see your:
  • Client ID
  • Client Secret
The Client ID and Client Secret are shown only once. Copy and store them immediately. If you lose them, you’ll need to create new credentials from the Admin tool.
3

Configure credentials in Open Wearables

Add the following to your .env file:
#--- Polar ---#
POLAR_CLIENT_ID=your-polar-client-id
POLAR_CLIENT_SECRET=your-polar-client-secret
POLAR_REDIRECT_URI=http://localhost:8000/api/v1/oauth/polar/callback
Configuration details:
VariableDescription
POLAR_CLIENT_IDClient ID from the Polar AccessLink Admin panel
POLAR_CLIENT_SECRETClient Secret from the Polar AccessLink Admin panel
POLAR_REDIRECT_URIMust match the Authorization redirect URL registered in your Polar application. For local dev: http://localhost:8000/api/v1/oauth/polar/callback
The OAuth scope is hardcoded to accesslink.read_all which grants full read access to the AccessLink API. No additional scope configuration is needed.
4

Connect a user via OAuth

With credentials configured and your Open Wearables instance running, initiate the OAuth flow to connect a user’s Polar account.1. Get the authorization URL:
curl -X GET "http://localhost:8000/api/v1/oauth/polar/authorize?user_id={user_id}&redirect_uri=http://localhost:3000/users/{user_id}" \
  -H "X-Open-Wearables-API-Key: YOUR_API_KEY"
Response:
{
  "authorization_url": "https://flow.polar.com/oauth2/authorization?client_id=...&redirect_uri=...&response_type=code&scope=accesslink.read_all&state=...",
  "state": "abc123..."
}
2. Redirect the user to the authorization_url. They will log in to Polar Flow and authorize your app.3. Polar redirects back to the callback URI configured in your .env (POLAR_REDIRECT_URI). Open Wearables automatically exchanges the authorization code for access tokens and registers the user with the Polar API.4. Verify the connection was created:
curl -X GET "http://localhost:8000/api/v1/users/{user_id}/connections" \
  -H "X-Open-Wearables-API-Key: YOUR_API_KEY"
You should see a connection with "provider": "polar" and "status": "active".
The redirect_uri parameter in the authorize call is where the user is sent after the flow completes (e.g., back to your app). This is separate from POLAR_REDIRECT_URI in your .env, which is the server-side OAuth callback that Polar sends the authorization code to.
5

Sync data

An initial sync is triggered automatically after a successful OAuth connection. To manually sync or fetch data:
# Sync all data types
curl -X POST "http://localhost:8000/api/v1/providers/polar/users/{user_id}/sync?data_type=all" \
  -H "X-Open-Wearables-API-Key: YOUR_API_KEY"
Polar only returns exercises uploaded within the last 30 days. Older data is not accessible via the AccessLink API.
6

Verify the integration

Once data has synced, fetch it via the Open Wearables API:
# Fetch workouts
curl -X GET "http://localhost:8000/api/v1/users/{user_id}/events/workouts?start_date=2026-01-01T00:00:00Z&end_date=2026-02-01T00:00:00Z" \
  -H "X-Open-Wearables-API-Key: YOUR_API_KEY"
You can also fetch raw Polar exercise data with optional samples, zones, and route data:
# Fetch Polar exercises with HR samples and route
curl -X GET "http://localhost:8000/api/v1/vendor-workouts/polar/users/{user_id}/workouts?samples=true&zones=true&route=true" \
  -H "X-Open-Wearables-API-Key: YOUR_API_KEY"
If data is returned, your Polar integration is working end-to-end.

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Rate Limits

Polar AccessLink API uses dynamic rate limits that scale with your registered user count:
LimitFormula
Per 15 minutes500 + (registered users x 20)
Per 24 hours5,000 + (registered users x 100)
Rate limit headers are included in every response: RateLimit-Usage, RateLimit-Limit, RateLimit-Reset.

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Next Steps

API Reference

Explore the Open Wearables API endpoints.

Architecture

Understand the overall system architecture.

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Support

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