SFN / Client / send_task_heartbeat



Used by activity workers and Task states using the callback pattern, and optionally Task states using the job run pattern to report to Step Functions that the task represented by the specified taskToken is still making progress. This action resets the Heartbeat clock. The Heartbeat threshold is specified in the state machine’s Amazon States Language definition ( HeartbeatSeconds). This action does not in itself create an event in the execution history. However, if the task times out, the execution history contains an ActivityTimedOut entry for activities, or a TaskTimedOut entry for tasks using the job run or callback pattern.


The Timeout of a task, defined in the state machine’s Amazon States Language definition, is its maximum allowed duration, regardless of the number of SendTaskHeartbeat requests received. Use HeartbeatSeconds to configure the timeout interval for heartbeats.

See also: AWS API Documentation

Request Syntax

response = client.send_task_heartbeat(

taskToken (string) –


The token that represents this task. Task tokens are generated by Step Functions when tasks are assigned to a worker, or in the context object when a workflow enters a task state. See GetActivityTaskOutput$taskToken.

Return type:



Response Syntax


Response Structure

  • (dict) –


  • SFN.Client.exceptions.TaskDoesNotExist

  • SFN.Client.exceptions.InvalidToken

  • SFN.Client.exceptions.TaskTimedOut