With AWS Step Functions, you pay only for what you use. You are charged based on the number of state transitions required to execute your application.
Step Functions pricing details
Step Functions counts a state transition each time a step of your workflow is executed. You are charged for the total number of state transitions across all your state machines, including retries.
The Step Functions free tier includes 4,000 free state transitions per month. All charges are metered daily and billed monthly.
For details, see the Step Functions pricing examples.
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.
With AWS Step Functions, you pay for the number state transitions you use per month. You are charged per state transition above the free tier. See the State Transitions Pricing Table for details. _
If you include retry error handling in any steps of your workflow, each retry will be charged as an additional state transition.
State transitions pricing
Additional charges
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 follow.
External data transfers to and from Amazon EC2
Requests and duration
On-Demand, Reserved, and Spot Instances
Fargate and EC2 Launch Types
Step Functions pricing examples
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Example 1
Application workflow with sequential stepsAn application workflow with two steps has three state transitions, determined by counting the arrows on the graph:
- Start to Upload RAW File
- Upload RAW File to Delete RAW File
- Delete RAW File to End
The price per state transition in US East (N. Virginia) is $0.000025 and the Free Tier provides 4,000 state transitions per month. If you executed this state machine 100,000 times during one month, without any retries dues to errors, you would pay:
State transitions in workflow * executions of workflow = total state transitions
3 * 100,000 = 300,000
Total state transitions – Free Tier state transitions = billable state transitions
300,000 – 4,000 = 296,000
Monthly charges = 296,000 * $0.000025 = $7.40
- Start to Upload RAW File
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Example 2
Application workflow with branching conditionsThe 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.
The price per state transition in US East (N. Virginia) is $0.000025 and the Free Tier provides 4,000 state transitions per month. If you executed this application workflow 100,000 times during one month, the happy path succeeds every time, and there are no retries due to errors, you would pay:
State transitions per execution * executions of workflow = total state transitions
8 * 100,000 = 800,000
Total state transitions – Free Tier state transitions = billable state transitions
800,000 – 4,000 = 796,000
Monthly charges = 796,000 * $0.000025 = $19.90
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 image, the size and duration of the Lambda functions 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
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