# StartFailureModeAssessment
<a name="API_StartFailureModeAssessment"></a>

Start a failure mode assessment.

## Request Syntax
<a name="API_StartFailureModeAssessment_RequestSyntax"></a>

```
POST /v2/start-failure-mode-assessment HTTP/1.1
Content-type: application/json

{
   "clientToken": "{{string}}",
   "serviceArn": "{{string}}"
}
```

## URI Request Parameters
<a name="API_StartFailureModeAssessment_RequestParameters"></a>

The request does not use any URI parameters.

## Request Body
<a name="API_StartFailureModeAssessment_RequestBody"></a>

The request accepts the following data in JSON format.

 ** [clientToken](#API_StartFailureModeAssessment_RequestSyntax) **   <a name="ngresiliencehub-StartFailureModeAssessment-request-clientToken"></a>
Idempotency token.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 63.  
Pattern: `[A-Za-z0-9_.-]{0,63}`   
Required: No

 ** [serviceArn](#API_StartFailureModeAssessment_RequestSyntax) **   <a name="ngresiliencehub-StartFailureModeAssessment-request-serviceArn"></a>
ARN identifier.  
Type: String  
Length Constraints: Minimum length of 31.  
Pattern: `arn:(aws|aws-cn|aws-iso|aws-iso-[a-z]{1}|aws-us-gov):[A-Za-z0-9][A-Za-z0-9_/.-]{0,62}:([a-z]{2}-((iso[a-z]{0,1}-)|(gov-)){0,1}[a-z]+-[0-9]):[0-9]{12}:[A-Za-z0-9/][A-Za-z0-9:_/+.-]{0,1023}`   
Required: Yes

## Response Syntax
<a name="API_StartFailureModeAssessment_ResponseSyntax"></a>

```
HTTP/1.1 200
Content-type: application/json

{
   "assessmentId": "string",
   "assessmentStatus": "string",
   "serviceArn": "string",
   "startedAt": number
}
```

## Response Elements
<a name="API_StartFailureModeAssessment_ResponseElements"></a>

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

 ** [assessmentId](#API_StartFailureModeAssessment_ResponseSyntax) **   <a name="ngresiliencehub-StartFailureModeAssessment-response-assessmentId"></a>
The unique identifier of the started assessment.  
Type: String  
Length Constraints: Fixed length of 36.  
Pattern: `[0-9a-f]{8}-[0-9a-f]{4}-[0-5][0-9a-f]{3}-[089ab][0-9a-f]{3}-[0-9a-f]{12}` 

 ** [assessmentStatus](#API_StartFailureModeAssessment_ResponseSyntax) **   <a name="ngresiliencehub-StartFailureModeAssessment-response-assessmentStatus"></a>
The status of the started assessment.  
Type: String  
Valid Values: `NOT_STARTED | PENDING | IN_PROGRESS | FAILED | SUCCESS` 

 ** [serviceArn](#API_StartFailureModeAssessment_ResponseSyntax) **   <a name="ngresiliencehub-StartFailureModeAssessment-response-serviceArn"></a>
ARN identifier.  
Type: String  
Length Constraints: Minimum length of 31.  
Pattern: `arn:(aws|aws-cn|aws-iso|aws-iso-[a-z]{1}|aws-us-gov):[A-Za-z0-9][A-Za-z0-9_/.-]{0,62}:([a-z]{2}-((iso[a-z]{0,1}-)|(gov-)){0,1}[a-z]+-[0-9]):[0-9]{12}:[A-Za-z0-9/][A-Za-z0-9:_/+.-]{0,1023}` 

 ** [startedAt](#API_StartFailureModeAssessment_ResponseSyntax) **   <a name="ngresiliencehub-StartFailureModeAssessment-response-startedAt"></a>
The timestamp when the assessment started.  
Type: Timestamp

## Errors
<a name="API_StartFailureModeAssessment_Errors"></a>

For information about the errors that are common to all actions, see [Common Error Types](CommonErrors.md).

 ** AccessDeniedException **   
Access denied — caller lacks required permissions.  
HTTP Status Code: 403

 ** ConflictException **   
Conflict — resource already exists.  
HTTP Status Code: 409

 ** InternalServerException **   
Internal service error.  
HTTP Status Code: 500

 ** ResourceNotFoundException **   
Resource not found.    
 ** resourceId **   
The identifier of the resource that was not found.  
 ** resourceType **   
The type of the resource that was not found.
HTTP Status Code: 404

 ** ThrottlingException **   
Too many requests — rate limit exceeded.    
 ** retryAfterSeconds **   
The number of seconds to wait before retrying the request.
HTTP Status Code: 429

 ** ValidationException **   
Validation error — invalid input parameters.    
 ** fieldList **   
The list of fields that failed validation.  
 ** reason **   
The reason for the validation failure.
HTTP Status Code: 400

## See Also
<a name="API_StartFailureModeAssessment_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS Command Line Interface V2](https://docs.aws.amazon.com/goto/cli2/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for C\+\+](https://docs.aws.amazon.com/goto/SdkForCpp/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/resiliencehubv2-2026-02-17/StartFailureModeAssessment) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/resiliencehubv2-2026-02-17/StartFailureModeAssessment)