With AWS Step Functions, you pay only for what you use. Step Functions has two types of workflows: Standard Workflows and Express Workflows.
AWS Step Functions Standard Workflows pricing details
You are charged based on the number of state transitions required to execute your application.
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.
AWS Step Functions Standard Workflow State transitions pricing
AWS Step Functions Express Workflows pricing details
With Step Functions Express Workflows, you pay only for what you use. You are charged based on the number of requests for your workflow and the duration, the time it takes for your workflow to execute.
Step Functions Express Workflows counts a request each time it starts executing a workflow, including tests from the console. You are charged for the total number of requests across all your workflows.
Duration is calculated from the time your workflow begins executing until it completes or otherwise terminates, rounded up to the nearest 100ms, and the amount of memory used in the execution of your workflow, billed in 64-MB chunks.
Memory consumption is based on the size of a workflow definition, the use of map or parallel states, and the execution (payload) data size. Pricing examples 3 and 4 show examples of estimating memory utilization.
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
AWS Step Functions standard 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
AWS Step Functions standard 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 -
Example 3
AWS Step Functions Express WorkflowsYou can estimate an AWS Step Functions Express Workflow’s memory utilization based on the size of the state machine definition, the execution (payload) data size, and the use of Map or Parallel states.
Workflow memory utilized = 50 MB + state machine definition size + execution data size x Number of Parallel or Map Steps
If you have a workflow with a 10 KB state machine definition size, and no parallel or map steps:
Workflow memory utilized = 50 MB + 10 KBWorkflow memory utilized = 50.01 MBBilled memory (in 64 MB chunks) = 64 MBCloudWatch Metrics contains details on memory consumption under ExpressExecutionMemory and billed memory under ExpressExecutionBilledMemory.
If you run 1 million of these workflows a month, and the average duration of the workflows is 30 seconds:
Monthly request charges
The price is $1.00 per million requestsMonthly request charges = 1M requests x $1.00 = $1.00Monthly duration charges
The price is $0.00001667 per GB-second of duration1 million workflows x 30 seconds of duration = 30,000,000 seconds30,000,000 x 64 MB (billed memory) /1024 MB = 1,875,000 GB-sMonthly duration charges = 1,875,000 GB-s x $0.00001667 = $31.26Total monthly charges
Total monthly charges = request charges + duration chargesTotal monthly charges = $1.00 + $31.26 = $32.26
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Example 4
AWS Step Functions Express WorkflowsYou can estimate an AWS Step Functions Express Workflow’s memory utilization based on the size of the state machine definition, the execution (payload) data size, and the use of Map or Parallel states.
Workflow memory utilized = 50 MB + state machine definition size + execution data size x Number of Parallel or Map Steps
If you have a workflow with a 50 KB state machine definition size, 400 map steps with 32 KB of payload per step:
Workflow memory utilized = 50 MB + 50 KB + (32 KB x 400 steps)
Workflow memory utilized = 50 MB + 50 KB + 12,800 KB
Workflow memory utilized = 62.85 MB
Billed memory (in 64 MB chunks) = 64 MBCloudWatch Metrics contains details on memory consumption under ExpressExecutionMemory and billed memory under ExpressExecutionBilledMemory.
If you run 100 million of these workflows a month, and the average duration of the workflows is 10 seconds:
Monthly request charges
The price is $1.00 per million requests
Monthly request charges = 100M requests x $1.00 = $100.00Monthly duration charges
100 million workflows x 10 seconds of duration = 1,000,000,000 seconds
1,000,000,000 x 64 MB (billed memory) /1024 MB = 62,500,000 GB-s
62,500,000 GB-s / 60 / 60 = 17,361.11 GB-hours
$0.06000 per GB-hour x 1,000 GB-Hours = $60.00
$0.03000 per GB-hour x 4,000 GB-Hours = $120.00
$0.01643 per GB-hour x 12,361.11 GB-Hours = $203.09Monthly duration charges = $60.00+$120.00+$203.09 = 383.09
Total monthly charges
Total monthly charges = request charges + duration charges
Total monthly charges = $100.00 + $383.09 = $483.09
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