# Polling

> Asking a device or service for new data on an interval. The opposite is push, where the device sends updates when something changes.

Source: https://contributors.home-assistant.io/glossary/polling/

- In code: `should_poll`, `SCAN_INTERVAL`, `update_interval`
- Also: poll, push

Push is faster and puts less load on devices and networks, so integrations use it when the device supports it. Otherwise, a [coordinator](https://contributors.home-assistant.io/glossary/coordinator/) polls on a fixed interval.

## Related terms

- [Coordinator](https://contributors.home-assistant.io/glossary/coordinator/): A helper that fetches data for many entities at once, on a schedule, so a device or API is asked once instead of once per entity.
- [IoT class](https://contributors.home-assistant.io/glossary/iot-class/): How an integration gets its data: locally or from the cloud, and by polling or push. Set in the manifest.