# Application-level heartbeats

You can define an application-level heartbeat for Transformer, so that client applications can check whether Transformer is running.

Application level heartbeats work by creating a special heartbeat object with a [symbol name (subject)](../datasource/datasource-subjects-symbols-and-fields.md) defined by the [`heartbeat-symbol`](transformer-heartbeats-configuration.md#heartbeat-symbol) configuration item. This object contains a timestamp field and the [`heartbeat-symbol-time`](transformer-heartbeats-configuration.md#heartbeat-symbol-time) configuration item defines how often Transformer updates this field. Every time Transformer updates the time stamp field, the update is propagated (usually via a [Liberator](../liberator/index.md)) to applications that have subscribed to the heartbeat object.

**📌 NOTE**\
You can also configure DataSource heartbeats for each [DataSource application](../datasource/index.md) ([Liberator](../liberator/index.md), [Integration Adapter](../platform-architecture/putting-data-into-the-platform.md)) connected to Transformer: see How can I... [Enable heartbeats between DataSource applications](../datasource/datasource-enable-heartbeats-between-datasource-applications.md).

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**See also:**

* Reference: [Heartbeats configuration in Transformer](transformer-heartbeats-configuration.md)