polar-flow

Modern async Python client for Polar AccessLink API.

Features

• Async-first with httpx
• Full type safety with Pydantic 2 and mypy strict mode
• Python 3.11+ with modern syntax
• Complete V3 API coverage
• 90%+ test coverage

API Coverage

Complete Polar AccessLink V3 API implementation:

• OAuth2 authentication with HTTP Basic Auth
• Sleep endpoint (get/list sleep data)
• Exercises endpoint (list/get/samples/zones/export TCX/GPX)
• Activity endpoint (daily activity with steps/zones/inactivity)
• Nightly Recharge endpoint (ANS charge, HRV, breathing rate)
• Users endpoint (register/get/delete)
• Physical Information endpoint (transaction-based body metrics)
• CLI authentication tool

All endpoints tested and validated against real Polar API.

Install

pip install polar-flow-api

Quick Start

1. Get Access Token

# Set your Polar API credentials
export CLIENT_ID="your_client_id"
export CLIENT_SECRET="your_client_secret"

# Run interactive OAuth flow
polar-flow auth

This opens your browser, handles the OAuth callback, and saves the token to ~/.polar-flow/token.

2. Use the Client

import asyncio
from polar_flow import PolarFlow

async def main():
    async with PolarFlow(access_token="your_token") as client:
        # Get sleep data
        sleep_data = await client.sleep.list(user_id="self", days=7)
        for night in sleep_data:
            print(f"{night.date}: {night.sleep_score}/100 ({night.total_sleep_hours:.1f}h)")

        # Get exercises
        exercises = await client.exercises.list()
        for ex in exercises:
            print(f"{ex.start_time}: {ex.sport} - {ex.duration_minutes}min, {ex.calories}cal")

asyncio.run(main())

OAuth2 Flow

from polar_flow.auth import OAuth2Handler

oauth = OAuth2Handler(
    client_id="your_client_id",
    client_secret="your_client_secret",
    redirect_uri="http://localhost:8888/callback"
)

# Get authorization URL
auth_url = oauth.get_authorization_url()
print(f"Visit: {auth_url}")

# After user authorizes, exchange code for token
token = await oauth.exchange_code(code="authorization_code")
print(f"Access token: {token.access_token}")

Sleep API

# Get sleep for specific date
sleep = await client.sleep.get(user_id="self", date="2026-01-09")
print(f"Sleep score: {sleep.sleep_score}")
print(f"Total sleep: {sleep.total_sleep_hours}h")
print(f"Deep sleep: {sleep.deep_sleep_seconds / 3600:.1f}h")
print(f"REM sleep: {sleep.rem_sleep_seconds / 3600:.1f}h")
print(f"HRV average: {sleep.hrv_avg}ms")

# List sleep data for date range
sleep_list = await client.sleep.list(user_id="self", days=7)
for night in sleep_list:
    print(f"{night.date}: score {night.sleep_score}, {night.total_sleep_hours:.1f}h")

Exercises API

# List exercises (last 30 days)
exercises = await client.exercises.list()
for ex in exercises:
    print(f"{ex.start_time}: {ex.sport}")
    print(f"  Duration: {ex.duration_minutes} min")
    print(f"  Calories: {ex.calories}")
    if ex.distance_km:
        print(f"  Distance: {ex.distance_km} km")
    if ex.average_heart_rate:
        print(f"  Avg HR: {ex.average_heart_rate} bpm")

# Get detailed exercise
exercise = await client.exercises.get(exercise_id="123")

# Get exercise samples (HR, speed, cadence, altitude)
samples = await client.exercises.get_samples(exercise_id="123")
hr_sample = samples.get_sample_by_type("0")  # 0 = heart rate
if hr_sample:
    print(f"HR values: {hr_sample.values[:10]}")  # First 10 values

# Get heart rate zones
zones = await client.exercises.get_zones(exercise_id="123")
for zone in zones.zones:
    print(f"Zone {zone.index}: {zone.lower_limit}-{zone.upper_limit} bpm, {zone.in_zone_minutes} min")

# Export to TCX/GPX
tcx_xml = await client.exercises.export_tcx(exercise_id="123")
gpx_xml = await client.exercises.export_gpx(exercise_id="123")

Error Handling

from polar_flow.exceptions import (
    AuthenticationError,
    NotFoundError,
    RateLimitError,
    ValidationError,
)

try:
    data = await client.sleep.get(user_id="self", date="2026-01-09")
except AuthenticationError:
    print("Invalid or expired token")
except NotFoundError:
    print("No data for this date")
except RateLimitError as e:
    print(f"Rate limited. Retry after {e.retry_after} seconds")
except ValidationError as e:
    print(f"Invalid request: {e}")

CLI Commands

# Authenticate (opens browser)
polar-flow auth

# Authenticate with explicit credentials
polar-flow auth --client-id YOUR_ID --client-secret YOUR_SECRET

# Show version
polar-flow version

Development

git clone https://github.com/StuMason/polar-flow.git
cd polar-flow
uv sync --all-extras
uv run pytest

Requirements

• Python 3.11+
• Polar AccessLink API credentials from admin.polaraccesslink.com

Links

• Polar AccessLink API Docs
• Issues

License

MIT