# ListRegions
<a name="API_ListRegions"></a>

Lists all enabled Regions of an IAM Identity Center instance, including those that are being added or removed. This operation returns Regions with ACTIVE, ADDING, or REMOVING status.

The following actions are related to `ListRegions`:
+  [ AddRegion](https://docs.amazonaws.cn/singlesignon/latest/APIReference/API_AddRegion.html) 
+  [RemoveRegion](https://docs.amazonaws.cn/singlesignon/latest/APIReference/API_RemoveRegion.html) 
+  [DescribeRegion](https://docs.amazonaws.cn/singlesignon/latest/APIReference/API_DescribeRegion.html) 

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

```
{
   "InstanceArn": "string",
   "MaxResults": number,
   "NextToken": "string"
}
```

## Request Parameters
<a name="API_ListRegions_RequestParameters"></a>

For information about the parameters that are common to all actions, see [Common Parameters](CommonParameters.md).

The request accepts the following data in JSON format.

 ** [InstanceArn](#API_ListRegions_RequestSyntax) **   <a name="singlesignon-ListRegions-request-InstanceArn"></a>
The Amazon Resource Name (ARN) of the IAM Identity Center instance.  
Type: String  
Length Constraints: Minimum length of 10. Maximum length of 1224.  
Pattern: `arn:aws(-[a-z]{1,5}){0,3}:sso:::instance/(sso)?ins-[a-zA-Z0-9-.]{16}`   
Required: Yes

 ** [MaxResults](#API_ListRegions_RequestSyntax) **   <a name="singlesignon-ListRegions-request-MaxResults"></a>
The maximum number of results to return in a single call. Default is 100.  
Type: Integer  
Valid Range: Minimum value of 1. Maximum value of 100.  
Required: No

 ** [NextToken](#API_ListRegions_RequestSyntax) **   <a name="singlesignon-ListRegions-request-NextToken"></a>
The pagination token for the list API. Initially the value is null. Use the output of previous API calls to make subsequent calls.  
Type: String  
Length Constraints: Minimum length of 0. Maximum length of 2048.  
Pattern: `[-a-zA-Z0-9+=/_]*`   
Required: No

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

```
{
   "NextToken": "string",
   "Regions": [ 
      { 
         "AddedDate": number,
         "IsPrimaryRegion": boolean,
         "RegionName": "string",
         "Status": "string"
      }
   ]
}
```

## Response Elements
<a name="API_ListRegions_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.

 ** [NextToken](#API_ListRegions_ResponseSyntax) **   <a name="singlesignon-ListRegions-response-NextToken"></a>
The pagination token to be used in subsequent calls. If the value is null, then there are no more entries.  
Type: String  
Length Constraints: Minimum length of 0. Maximum length of 2048.  
Pattern: `[-a-zA-Z0-9+=/_]*` 

 ** [Regions](#API_ListRegions_ResponseSyntax) **   <a name="singlesignon-ListRegions-response-Regions"></a>
The list of Regions enabled in the IAM Identity Center instance, including Regions with ACTIVE, ADDING, or REMOVING status.  
Type: Array of [RegionMetadata](API_RegionMetadata.md) objects

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

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

 ** AccessDeniedException **   
You do not have sufficient access to perform this action.    
 ** Reason **   
The reason for the access denied exception.
HTTP Status Code: 400

 ** InternalServerException **   
The request processing has failed because of an unknown error, exception, or failure with an internal server.  
HTTP Status Code: 500

 ** ThrottlingException **   
Indicates that the principal has crossed the throttling limits of the API operations.    
 ** Reason **   
The reason for the throttling exception.
HTTP Status Code: 400

 ** ValidationException **   
The request failed because it contains a syntax error.    
 ** Reason **   
The reason for the validation exception.
HTTP Status Code: 400

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

For more information about using this API in one of the language-specific Amazon SDKs, see the following:
+  [Amazon Command Line Interface V2](https://docs.amazonaws.cn/goto/cli2/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for .NET V4](https://docs.amazonaws.cn/goto/DotNetSDKV4/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for C\$1\$1](https://docs.amazonaws.cn/goto/SdkForCpp/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for Go v2](https://docs.amazonaws.cn/goto/SdkForGoV2/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for Java V2](https://docs.amazonaws.cn/goto/SdkForJavaV2/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for JavaScript V3](https://docs.amazonaws.cn/goto/SdkForJavaScriptV3/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for Kotlin](https://docs.amazonaws.cn/goto/SdkForKotlin/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for PHP V3](https://docs.amazonaws.cn/goto/SdkForPHPV3/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for Python](https://docs.amazonaws.cn/goto/boto3/sso-admin-2020-07-20/ListRegions) 
+  [Amazon SDK for Ruby V3](https://docs.amazonaws.cn/goto/SdkForRubyV3/sso-admin-2020-07-20/ListRegions)