> ## Documentation Index
> Fetch the complete documentation index at: https://docs.junction.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Update Frequency

> Understand how Junction discovers new wearable data through push, polling, and hybrid update models across cloud-based providers.

Whenever Junction detects that new data is available, [data events](/event-catalog) are always sent to your configured endpoints,
regardless of the provider being push-based or polling-based.

## Cloud Based Providers

| Primary Model | Providers                                                                                                                                                                                                                                                                                                     |
| ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Hybrid        | [Fitbit](https://www.fitbit.com/global/uk/home), [Withings](https://www.withings.com), [Oura](https://ouraring.com)                                                                                                                                                                                           |
| Push          | [Garmin](https://www.garmin.com), [Strava](https://www.strava.com), [WHOOP](https://www.whoop.com), [Cronometer](https://www.cronometer.com)                                                                                                                                                                  |
| Polling       | [Wahoo](https://wahoofitness.com), [LibreView](https://www.libreview.com/), [Google Fit](https://www.google.com/fit/), [Peloton](https://www.onepeloton.com), [Zwift](https://zwift.com), [EightSleep](https://www.eightsleep.com), [Hammerhead](https://www.hammerhead.io), [Dexcom](https://www.dexcom.com) |

Cloud Based Providers can operate in the following three models:

<AccordionGroup>
  <Accordion title="Push" defaultOpen>
    In the Push model, the data provider proactively notifies Junction of any resource changes.

    Junction goes and fetches the notified resources, compares them against what we have already ingested, and sends out the differences
    (new or updated entities) to your Webhook endpoints or ETL Pipeline destinations.

    While resources using the Push model typically have lower latency than polling, data providers may impose throttling, debouncing
    or batching semantics on these push notifications to Junction on their end.
  </Accordion>

  <Accordion title="Polling" defaultOpen>
    Junction schedules a recurring job to query the data provider API resources:

    * For most resources, the schedule is every 15 minutes or so.
    * Some resources may use a sparser schedule due to data provider rate limits.

    Junction then compares the reported data against what we have already ingested, and sends out the differences
    (new or updated entities) to your Webhook endpoints or ETL Pipeline destinations.
  </Accordion>

  <Accordion title="Hybrid" defaultOpen>
    Some data providers support the Push model only on a subset of API resources.

    Junction prefers to use the Push model whenever available, but otherwise falls back to the Polling model.
  </Accordion>
</AccordionGroup>

## SDK Based Providers

SDK Based Providers are all push-based, where data are pushed from the Junction SDK embedded inside your Android or iOS app.

| Provider                                                               | Description                                                                                                          |
| ---------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------- |
| [Apple HealthKit](https://www.apple.com/uk/ios/health/)                | <ul><li>Auto sync on app launch and in foreground</li><li>Hourly Background Sync, subject to OS throttling</li></ul> |
| [Android Health Connect](https://developer.android.com/health-connect) | <ul><li>Sync On App Launch</li><li>Opt-in Hourly Background Sync, subject to OS throttling</li></ul>                 |
| [Samsung Health](https://developer.samsung.com/health/data)            | <ul><li>Sync On App Launch</li><li>Opt-in Hourly Background Sync, subject to OS throttling</li></ul>                 |
| [Omron](https://www.omron-healthcare.com)                              | Manual Post                                                                                                          |
| [Contour](https://www.diabetes.ascensia.com)                           | Manual Post                                                                                                          |
| [Accu-Chek](https://www.accu-chek.com)                                 | Manual Post                                                                                                          |

For more information on Apple HealthKit, Android Health Connect and Samsung Health, please refer to the specific guides:

* [Junction Health SDK: Automatic Data Sync](/wearables/sdks/health/overview#automatic-data-sync)
* [Apple HealthKit: Sync Frequency](/wearables/guides/apple-healthkit#sync-frequency)
* [Android Health Connect: Synchronization](/wearables/guides/android-health-connect#synchronization)
* [Samsung Health: Background Sync](/wearables/guides/samsung-health#background-sync)