Quotas

AWS Step Functions places quotas on the sizes of certain state machine parameters, such as the number of API actions during a certain time period or the number of state machines that you can define. Although these quotas are designed to prevent a misconfigured state machine from consuming all of the resources of the system, many aren't hard quotas. Use the Support Center page in the AWS Management Console to request a quota increase for resources provided by AWS Step Functions on a per-Region basis. For more information, see AWS service quotas in the AWS General Reference.

Note

If a particular stage of your state machine execution or activity execution takes too long, you can configure a state machine timeout to cause a timeout event.

General quotas

Quota

Description

Names in Step Functions

State machine, execution, and activity names must be 1–80 characters in length, must be unique for your account and AWS Region, and must not contain any of the following: Whitespace Wildcard characters (? *) Bracket characters (< > { } [ ]) Special characters (: ; , \ | ^ ~ $ # % & ` ") Control characters (\\u0000 - \\u001f or \\u007f - \\u009f). If your state machine is of type Express, you can provide the same name to multiple executions of the state machine. Step Functions generates a unique execution ARN for each Express state machine execution, even if multiple executions have the same name. Step Functions allows you to create state machine, execution, and activity names that contain non-ASCII characters. These non-ASCII names don't work with Amazon CloudWatch. To ensure that you can track CloudWatch metrics, choose a name that uses only ASCII characters.

Quotas related to accounts

Resource	Default quota	Can be increased to
Maximum number of registered state machines	10,000	25,000
Maximum number of registered activities	10,000	15,000
Maximum request size	1 MB per request. This is the total data size per Step Functions API request, including the request header and all other associated request data.	Hard quota
Maximum open executions per account	1,000,000 executions for each AWS account in each AWS Region. Exceeding this will cause an ExecutionLimitExceeded error. Does not apply to Express Workflows.	Millions
Synchronous Express Workflows concurrent executions	1,000-3,700 (varies per region)	Tens of thousands. Synchronous Express Workflows do not contribute to the existing account capacity limits. For more information, see Synchronous and Asynchronous Express Workflows.

Quotas related to state throttling

Step Functions state transitions are throttled using a token bucket scheme to maintain service bandwidth. Standard Workflows and Express Workflows have different state transition throttling. Standard Workflows quotas are soft quotas and can be increased.

Note

Throttling on the StateTransition service metric is reported as ExecutionThrottled in Amazon CloudWatch. For more information, see the ExecutionThrottled CloudWatch metric.

	Standard		Express
Service metric	Bucket size	Refill rate per second	Bucket size	Refill rate per second
StateTransition — In US East (N. Virginia), US West (Oregon), and Europe (Ireland)	5,000	1,500	Unlimited	Unlimited
StateTransition — All other regions	800	500	Unlimited	Unlimited

Quotas related to API action throttling

Some Step Functions API actions are throttled using a token bucket scheme to maintain service bandwidth. These quotas are soft quotas and can be increased.

Note

Throttling quotas are per account, per AWS Region. AWS Step Functions may increase both the bucket size and refill rate at any time. Synchronous Express execution API calls do not contribute to the existing account capacity limits. While Step Functions will provide capacity on demand and will automatically scale with sustained workload, surges in workload may be throttled until capacity is available. Do not rely on these throttling rates to limit your costs.

	Standard		Express
API name	Bucket size	Refill rate per second	Bucket size	Refill rate per second
StartExecution — In US East (N. Virginia), US West (Oregon), and Europe (Ireland)	1,300	300	6,000	6,000
StartExecution — All other regions	800	150	6,000	6,000

Quotas related to state machine executions

The following table describes quotas related to state machine executions. State machine execution quotas are hard quotas that can't be changed, except for the Execution history retention time quota.

Quota	Standard	Express
Maximum execution time	1 year. If an execution runs for more than the 1-year maximum, it will fail with a States.Timeout error and emit a ExecutionsTimedOut CloudWatch metric.	5 minutes. If an execution runs for more than the 5-minute maximum, it will fail with a States.Timeout error and emit a ExecutionsTimedOut CloudWatch metric.
Maximum execution history size	25,000 events in a single state machine execution history. If the execution history reaches this quota, the execution will fail. To avoid this, see Avoid reaching the history quota.	Unlimited.
Maximum execution idle time	1 year (constrained by the maximum execution time)	5 minutes (constrained by the maximum execution time)
Execution history retention time	90 days after an execution is closed. After this time, you can no longer retrieve or view the execution history. There is no further quota for the number of closed executions that Step Functions retains. To meet compliance, organizational, or regulatory requirements, you can reduce the execution history retention period to 30 days by sending a quota request. To do this, use the AWS Support Center Console and create a new case. The change to reduce the retention period to 30 days is applicable at the account level.	To see execution history, Amazon CloudWatch Logs logging must be configured. For more information, Logging using CloudWatch Logs.

Quotas related to task executions

The following table describes quotas related to task executions, and are hard quotas that can't be changed.

Quota	Standard	Express
Maximum task execution time	1 year (constrained by the maximum execution time)	5 minutes (constrained by the maximum execution time)
Maximum time Step Functions keeps a task in the queue	1 year (constrained by the maximum execution time)	5 minutes (constrained by the maximum execution time)
Maximum activity pollers per Amazon Resource Name (ARN)	1,000 pollers calling GetActivityTask per ARN. Exceeding this quota results in this error: "The maximum number of workers concurrently polling for activity tasks has been reached."	Does not apply to Express Workflows.
Maximum input or output size for a task, state, or execution	262,144 bytes of data as a UTF-8 encoded string. This quota affects tasks (activity, Lambda function, or integrated service), state or execution output, and input data when scheduling a task, entering a state, or starting an execution.	262,144 bytes of data as a UTF-8 encoded string. This quota affects tasks (activity, Lambda function, or integrated service), state or execution output, and input data when scheduling a task, entering a state, or starting an execution.

Other quotas

These quotas are soft quotas and can be increased.

	In US East (N. Virginia), US West (Oregon), and Europe (Ireland)		All other regions
API name	Bucket size	Refill rate per second	Bucket size	Refill rate per second
CreateActivity	100	1	100	1
CreateStateMachine	100	1	100	1
DeleteActivity	100	1	100	1
DeleteStateMachine	100	1	100	1
DescribeActivity	200	1	200	1
DescribeExecution	300	15	250	10
DescribeStateMachine	200	20	200	20
DescribeStateMachineForExecution	200	1	200	1
GetActivityTask	3,000	500	1,500	300
GetExecutionHistory	400	20	400	20
ListActivities	100	10	100	5
ListExecutions	200	5	100	2
ListStateMachines	100	5	100	5
ListTagsForResource	100	1	100	1
SendTaskFailure	3,000	500	1,500	300
SendTaskHeartbeat	3,000	500	1,500	300
SendTaskSuccess	3,000	500	1,500	300
StopExecution	1,000	200	500	25
TagResource	200	1	200	1
UntagResource	200	1	200	1
UpdateStateMachine	100	1	100	1

Restrictions related to tagging

Be aware of these restrictions when tagging Step Functions resources.

Note

Tagging restrictions cannot be increased like other quotas.

Restriction	Description
Maximum number of tags per resource	50
Maximum key length	128 Unicode characters in UTF-8
Maximum value length	256 Unicode characters in UTF-8
Prefix restriction	Do not use the aws: prefix in your tag names or values because it is reserved for AWS use. You can't edit or delete tag names or values with this prefix. Tags with this prefix do not count against your tags per resource quota.
Character restrictions	Tags may only contain Unicode letters, digits, whitespace, or these symbols: _ . : / = + - @