AWS Step Functions come in two flavours: Standard and Express. They share a definition language called ASL, but a lot of the API operations are not supported across both types. I didn’t find a good side-by-side comparison showing the support for each individual API operation, so I made one. This could help you decide if your Standard workflows could be replaced by Express workflows.

There is a good side-by-side comparison for an overview of the two types of workflow. Understanding those differences helps to explain why certain operations are not supported.

Takeaways

  • Activities and the Callback pattern are not supported.
  • Execution data is not available via the Step Functions API, only via CloudWatch Logs.
  • Thinking of Express workflows as “ASL executed on Lambda” was a decent mental model.
Category Operation Standard Express
State Machine createStateMachine
  updateStateMachine
  deleteStateMachine
  describeStateMachine
  listStateMachines
Execution startExecution
  startSyncExecution
  stopExecution
  getExecutionHistory
  describeExecution
  listExecutions
  describeStateMachineForExecution
Activities createActivity
  deleteActivity
  listActivities
  describeActivity
  getActivityTask
Callback sendTaskFailure
  sendTaskSuccess
  sendTaskHeartbeat
Tags tagResource
  untagResource
  listTagsForResource


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ABOUT GRUNDLEFLECK

Graham "Grundlefleck" Allan is a Software Developer living in Scotland. His only credentials as an authority on software are that he has a beard. Most of the time.

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