With AWS Step Functions, you pay only for what you use. You are charged based on the number of state transitions to complete the end-to-end workflow of your application. The Step Functions free tier includes 4,000 free state transitions per month. All charges are metered daily and billed monthly.

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The AWS Step Functions free tier includes 4,000 state transitions each month.  

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As you move from one step of your application workflow to the next, you transition between states, referred to as a state transition. With AWS Step Functions, you pay for each state transition, beginning with the transition from the start of your application workflow to the first step, and completing with the transition from the final step to the end of your application workflow. For details, see the Step Functions pricing examples.

  • 4,000 state transitions are free each month
  • $0.025 per 1,000 state transitions thereafter ($0.000025 per state transition)

The AWS Step Functions free tier includes 4,000 state transitions each month. The Step Functions free tier does not automatically expire at the end of your 12 month AWS Free Tier term, and is available to both existing and new AWS customers indefinitely.

You may incur additional charges if the operation of your application workflow utilizes other AWS services or transfers data. For example, if your application workflow invokes an AWS Lambda function, you will be billed for each request and for the duration of each Lambda function.

For details on AWS service pricing, see the pricing section of the relevant AWS service detail pages. Links to pricing for some of the commonly used services are in the following list:

  • Data transfer - if your application workflow initiates external data transfers, they will be charged at the Amazon EC2 data transfer rate
  • AWS Lambda pricing - includes pricing for requests and duration
  • Amazon EC2 pricing - includes pricing for On-Demand, Reserved Instances, and Spot Instances

Except as otherwise noted, our prices are exclusive of applicable taxes and duties, including VAT and applicable sales tax. For customers with a Japanese billing address, use of AWS is subject to Japanese Consumption Tax. Learn more.


2-Step_Application

An application workflow with two steps has three state transitions, determined by counting the arrows (or arcs) on the graph: one transition from the Start of the workflow to the Upload RAW File step, one from the Upload RAW File step to the Delete RAW File step, and a final transition from the Delete RAW File step to the End of your application workflow.

However, if you included retry error handling in the Upload RAW File or Delete RAW File steps, then each retry required would be charged for an additional state transition. You may think of retry as looping on the state. If you executed this state machine 100,000 times during one month, then without any retries dues to errors, you would pay:

Total State Transitions: 3 state transitions per execution x 100,000 executions = 300,000 state transitions

Monthly Charges: 300,000 state transitions x $0.000025 per state transition = *$7.50 per month

*Less free tier adjustment of 4,000 free state transitions per month.


App_Workflow_Multiple_Paths

The state machine used in this example may be found on github.

An application workflow with branching conditions has more than one path. In this example, there are 10 arrows (or arcs) connecting steps. The happy path from “Start” to “End” flows through eight state transitions. Paths that flow from “Start” to the “NotSupportedImageType” will accumulate two or three state transitions. Additional state transitions may be charged if retry error handling is included in any state.

If you executed this application workflow 100,000 times during one month, and the happy path succeeds, then without any retries due to errors, you would pay:

Total State Transitions: 8 state transitions x 100,000 executions = 800,000 state transitions

Monthly Step Functions Charges: 800,000 state transitions x $0.000025 per state transition = $20.00* per month.

*Less free tier adjustment of 4,000 free state transitions per month.

For reference, the total cost of the five AWS Lambda functions in this example would be $97.62. In a successful happy path execution processing a 4.7 MB JPEG photograph, the Lambda functions size and duration are as follows:

Function   Memory (MB)     Duration (Msec)  
ExtractImageMetadata 1,024 3,200
TransformMetadata 256 100
Rekognition 256 1,200
Thumbnail 1,536 1,500
StoreImageMetadata 256 300