# Step Functions service quotas
Service quotas

AWS Step Functions provide default service quotas for state machine parameters, such as the number of API actions during a time period or the number of state machines that you can define. Quotas are designed to prevent misconfigured state machine from consuming all of the resources of the system, although many do not have hard limits. 

To request a service quota increase, you can do one of the following:
+ Use the Service Quotas console at [https://console.aws.amazon.com/servicequotas/home](https://console.aws.amazon.com/servicequotas/home). For information about requesting a quota increase using the Service Quotas console, see [Requesting a quota increase](https://docs.aws.amazon.com/servicequotas/latest/userguide/request-quota-increase.html) in the *Service Quotas User Guide*.
+ 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](https://docs.aws.amazon.com/general/latest/gr/aws_service_limits.html) in the *AWS General Reference*.

**Important**  
New AWS accounts have reduced state transition quotas. AWS raises these quotas automatically based on your usage.

**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.

**Topics**
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## General quotas
](#service-limits-general)
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## Quotas related to accounts
](#service-limits-accounts)
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## Quotas related to HTTP Task
](#service-limits-http-task)
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## Quotas related to state throttling
](#service-limits-api-state-throttling)
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## Quotas related to API action throttling
](#service-limits-api-action-throttling-general)
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## Quotas related to state machine executions
](#service-limits-state-machine-executions)
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## Quotas related to task executions
](#service-limits-task-executions)
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## Quotas related to versions and aliases
](#quotas-versions-aliases)
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## Restrictions related to tagging
](#sfn-limits-tagging)

## General quotas


Names of state machines, executions, and activity tasks must not exceed 80 characters in length. These names 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`).

Step Functions accepts names for state machines, executions, activities, and labels that contain non-ASCII characters. Because such characters will prevent Amazon CloudWatch from logging data, we recommend using only ASCII characters so you can track Step Functions metrics.

## Quotas related to accounts



| Resource | Default quota | Can be increased to | 
| --- | --- | --- | 
| Maximum number of registered state machines | 100,000 | 150,000 | 
|  Maximum number of registered activities  | 100,000 | 150,000 | 
|  Maximum size of state machine definition  | 1 MB | Hard quota | 
| 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 limit will cause an ExecutionLimitExceeded error. This doesn't apply to Express Workflows. | Millions | 
| Maximum number of open Map Runs | 1000 This quota applies to [*Distributed Map state*](state-map-distributed.md). An open [Map Run](concepts-examine-map-run.md) has started, but hasn't yet completed. Backlogged Map Runs wait at the [MapRunStarted](https://docs.aws.amazon.com/step-functions/latest/apireference/API_MapRunStartedEventDetails.html) event until the total number of open Map Runs is less than the quota. | Hard quota | 
| Maximum [redrives](redrive-map-run.md) of a Map Run. | 1000 This quota applies to *Distributed Map state*. | Hard quota | 
| Maximum number of parallel Map Run child executions | 10,000 |  Hard quota  | 

## Quotas related to HTTP Task


HTTP Tasks are throttled using a token bucket scheme to maintain the Step Functions service bandwidth.


| Resource | Bucket size | Refill rate per second | 
| --- | --- | --- | 
| [HTTP Task](call-https-apis.md) | 300 | 300 | 


| Resource | Default quota | 
| --- | --- | 
| HTTP Task duration — time to send an HTTP request and receive a response | 60 seconds (Hard quota) | 

## 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](procedure-cw-metrics.md#cloudwatch-step-functions-execution-metrics).


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

## Quotas related to API action throttling


Some Step Functions API actions are throttled using a token bucket scheme to maintain service bandwidth. The following 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.


| ** ** | **Standard** | **Express** | 
| --- |--- |--- |
| API name | Bucket size | Refill rate per second | Bucket size | Refill rate per second | 
| --- |--- |--- |--- |--- |
| StartExecution — 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 | 

### Other quotas


The following are soft quotas and can be increased.


| ** ** | **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 | 
| CreateStateMachineAlias | 100 | 1 | 100 | 1 | 
| DeleteActivity | 100 | 1 | 100 | 1 | 
| DeleteStateMachine | 100 | 1 | 100 | 1 | 
| DeleteStateMachineAlias | 100 | 1 | 100 | 1 | 
| DeleteStateMachineVersion | 100 | 1 | 100 | 1 | 
| DescribeActivity | 200 | 1 | 200 | 1 | 
| DescribeExecution | 300 | 15 | 250 | 10 | 
| DescribeMapRun | 200 | 1 | 200 | 1 | 
| DescribeStateMachine | 200 | 20 | 200 | 20 | 
| DescribeStateMachineAlias | 200 | 1 | 200 | 1 | 
| 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 | 
| ListMapRuns | 100 | 1 | 100 | 1 | 
| ListStateMachineAliases | 100 | 1 | 100 | 1 | 
| ListStateMachines | 100 | 5 | 100 | 5 | 
| ListStateMachineVersions | 100 | 1 | 100 | 1 | 
| ListTagsForResource | 100 | 1 | 100 | 1 | 
| PublishStateMachineVersion | 100 | 1 | 100 | 1 | 
| RedriveExecution | 1,300 | 300 | 800 | 150 | 
| SendTaskFailure | 3,000 | 500 | 1,500 | 300 | 
| SendTaskHeartbeat | 3,000 | 500 | 1,500 | 300 | 
| SendTaskSuccess | 3,000 | 500 | 1,500 | 300 | 
| StartSyncExecution |  Synchronous Express execution API calls don't contribute to existing account capacity limits. Step Functions provides capacity on demand and automatically scales with sustained workload. Surges in workload may be throttled until capacity is available. If you experience throttling, try again after some time. For information about Synchronous Express workflows, see [Synchronous and Asynchronous Express Workflows in Step Functions](choosing-workflow-type.md#concepts-express-synchronous).  | 
| StopExecution | 1,000 | 200 | 500 | 25 | 
| TagResource | 200 | 1 | 200 | 1 | 
| TestState | 10 | 50 | 10 | 50 | 
| UntagResource | 200 | 1 | 200 | 1 | 
| UpdateMapRun | 100 | 1 | 100 | 1 | 
| UpdateStateMachine | 100 | 1 | 100 | 1 | 
| UpdateStateMachineAlias | 100 | 1 | 100 | 1 | 
| ValidateStateMachineDefinition | 100 | 1 | 100 | 1 | 

## 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 [Starting new executions to avoid reaching the history quota in Step Functions](sfn-best-practices.md#bp-history-limit). | Unlimited. | 
|  Maximum execution idle time  |  1 year Constrained by maximum execution time.  |  5 minutes Constrained by 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 for each account in a Region.  |  To see execution history, Amazon CloudWatch Logs logging must be configured. For more information, see [Using CloudWatch Logs to log execution history in Step Functions](cw-logs.md).  | 
| Execution redrivable period | 14 days Hard quota applies to [*Distributed Map state*](state-map-distributed.md). Redrivable period refers to the time during which you can [redrive](redrive-executions.md) a given [Standard Workflow](choosing-workflow-type.md) execution. This period starts from the day a state machine completes its execution.  | Redrive is not supported for Express workflows. | 

## Quotas related to task executions


The following table describes quotas related to task executions. These are all **hard quotas** that cannot be changed.


| Quota | Standard | Express | 
| --- | --- | --- | 
| Maximum task execution time | 1 year — Constrained by maximum execution time. | 5 minutes — Constrained by maximum execution time. | 
| Maximum time Step Functions keeps a task in the queue | 1 year — Constrained by maximum execution time. | 5 minutes — Constrained by maximum execution time. | 
| Maximum input or output size for a task, state, or execution | 256 KiB 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. | 256 KiB 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. | 

## Quotas related to versions and aliases



| Resource | Default quota | 
| --- | --- | 
| Maximum number of published state machine versions | 1000 per state machine | 
| Maximum number of state machine aliases | 100 per state machine | 

To request an increase to soft limits for published state machine versions and aliases, use the **Support Center** page in the [AWS Management Console](https://docs.aws.amazon.com/servicequotas/latest/userguide/request-quota-increase.html). 

## Restrictions related to tagging


The following tagging restrictions can **not** be modified or increased.
+ **Prefix restriction** — Do not use the `aws:` prefix in your tag names or values because it is reserved for AWS use only. You cannot edit or delete tag names or values with an `aws:` prefix. Tags with the `aws:` prefix do not count against your tags per resource quota.
+ **Character restrictions** — Tags may only contain Unicode letters, digits, whitespace, or the following symbols: `_ . : / = + - @`


| 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 |