Limits
AWS Step Functions places limits on the sizes of certain state machine parameters, such as the number of API actions that you can make during a certain time period or the number of state machines that you can define. Although these limits are designed to prevent a misconfigured state machine from consuming all of the resources of the system, they aren't hard limits.
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
General Limits
| Limit | 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:
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. |
Limits Related to Accounts
| Limit | Description |
|---|---|
|
Maximum number of registered activities |
10,000 |
| Maximum number of registered state machines | 10,000 |
|
Maximum number of API actions |
Beyond infrequent spikes, applications can be throttled if they make a large number of API actions in a very short period of time. |
|
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. |
Limits Related to State Machine Executions
| Limit | Description | ||
|---|---|---|---|
|
Maximum open executions |
1,000,000. Exceeding this limit will
cause an ExecutionLimitExceeded error.
|
||
|
Maximum execution time |
1 year. If an execution runs for more than the 1-year limit, it
will fail with a |
||
|
Maximum execution history size |
25,000 events. If the execution history reaches this limit the execution will fail. To avoid this, see Avoid Reaching the History Limit. | ||
|
Maximum execution idle time |
1 year (constrained by execution time limit) |
||
| Maximum execution history retention time |
90 days. After this time, you can no longer retrieve or view the execution history. There is no further limit to the number of closed executions that Step Functions retains. |
||
Limits Related to Task Executions
| Limit | Description |
|---|---|
|
Maximum task execution time |
1 year (constrained by execution time limit) |
|
Maximum time Step Functions keeps a task in the queue |
1 year (constrained by execution time limit) |
|
Maximum activity pollers per Amazon Resource Name (ARN) |
1,000 pollers calling |
|
Maximum input or result data size for a task, state, or execution |
32,768 characters. This limit affects tasks (activity or Lambda function), state or execution result data, and input data when scheduling a task, entering a state, or starting an execution. |
Limits Related to API Action Throttling
Some Step Functions API actions are throttled using a token bucket scheme to maintain service bandwidth.
Note
Throttling limits are per account, per AWS Region. AWS Step Functions may increase both the bucket size and refill rate at any time. Do not rely on these throttling rates to limit your costs.
| API Name | Bucket Size | Refill Rate per Second |
|---|---|---|
CreateActivity |
100 | 1 |
CreateStateMachine |
100 | 1 |
DeleteActivity |
100 | 1 |
DeleteStateMachine |
100 | 1 |
DescribeActivity |
200 | 1 |
DescribeExecution |
200 | 2 |
DescribeStateMachine |
200 | 1 |
DescribeStateMachineForExecution |
100 | 1 |
GetActivityTask |
1,000 | 25 |
GetExecutionHistory |
250 | 5 |
ListActivities |
100 | 1 |
ListExecutions |
100 | 2 |
ListStateMachines |
100 | 1 |
SendTaskFailure |
1,000 | 25 |
SendTaskHeartbeat |
1,000 | 25 |
SendTaskSuccess |
1,000 | 25 |
StartExecution — In US East (N. Virginia),
US West (Oregon), and EU (Ireland) |
1000 | 200 |
StartExecution — All other
Regions |
500 | 25 |
StopExecution — In US East (N. Virginia),
US West (Oregon), and EU (Ireland) |
1000 | 200 |
StopExecution — All other
Regions |
500 | 25 |
UpdateStateMachine |
200 | 1 |
Limits Related to State Throttling
Step Functions state transitions are throttled using a token bucket scheme to maintain service bandwidth.
Note
Throttling on the StateTransition service metric is reported as
ExecutionThrottled in Amazon CloudWatch. For more information, see the ExecutionThrottled CloudWatch metric.
| Service Metric | Bucket Size | Refill Rate per Second |
|---|---|---|
|
|
5000 |
1000 |
|
|
800 |
400 |
Restrictions Related to Tagging
Be aware of these restrictions when tagging Step Functions resources.
Note
Tagging restrictions cannot be increased like other limits.
| 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 |
|
Character restrictions |
Tags may only contain unicode letters, digits, whitespace, or
these symbols: |
Requesting a Limit Increase
Use the Support Center page in the AWS Management Console to request a limit increase for resources provided by AWS Step Functions on a per-Region basis. For more information, see To Request a Limit Increase in the AWS General Reference.
