# CreateMulticastGroup


Creates a multicast group.

## Request Syntax


```
POST /multicast-groups HTTP/1.1
Content-type: application/json

{
   "ClientRequestToken": "string",
   "Description": "string",
   "LoRaWAN": { 
      "DlClass": "string",
      "ParticipatingGateways": { 
         "GatewayList": [ "string" ],
         "TransmissionInterval": number
      },
      "RfRegion": "string"
   },
   "Name": "string",
   "Tags": [ 
      { 
         "Key": "string",
         "Value": "string"
      }
   ]
}
```

## URI Request Parameters


The request does not use any URI parameters.

## Request Body


The request accepts the following data in JSON format.

 ** [ClientRequestToken](#API_CreateMulticastGroup_RequestSyntax) **   <a name="iotwireless-CreateMulticastGroup-request-ClientRequestToken"></a>
Each resource must have a unique client request token. The client token is used to implement idempotency. It ensures that the request completes no more than one time. If you retry a request with the same token and the same parameters, the request will complete successfully. However, if you try to create a new resource using the same token but different parameters, an HTTP 409 conflict occurs. If you omit this value, AWS SDKs will automatically generate a unique client request. For more information about idempotency, see [Ensuring idempotency in Amazon EC2 API requests](https://docs.aws.amazon.com/ec2/latest/devguide/ec2-api-idempotency.html).  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 64.  
Pattern: `^[a-zA-Z0-9-_]+$`   
Required: No

 ** [Description](#API_CreateMulticastGroup_RequestSyntax) **   <a name="iotwireless-CreateMulticastGroup-request-Description"></a>
The description of the multicast group.  
Type: String  
Length Constraints: Maximum length of 2048.  
Required: No

 ** [LoRaWAN](#API_CreateMulticastGroup_RequestSyntax) **   <a name="iotwireless-CreateMulticastGroup-request-LoRaWAN"></a>
The LoRaWAN information that is to be used with the multicast group.  
Type: [LoRaWANMulticast](API_LoRaWANMulticast.md) object  
Required: Yes

 ** [Name](#API_CreateMulticastGroup_RequestSyntax) **   <a name="iotwireless-CreateMulticastGroup-request-Name"></a>
The name of the multicast group.  
Type: String  
Length Constraints: Maximum length of 256.  
Required: No

 ** [Tags](#API_CreateMulticastGroup_RequestSyntax) **   <a name="iotwireless-CreateMulticastGroup-request-Tags"></a>
The tag to attach to the specified resource. Tags are metadata that you can use to manage a resource.  
Type: Array of [Tag](API_Tag.md) objects  
Array Members: Minimum number of 0 items. Maximum number of 200 items.  
Required: No

## Response Syntax


```
HTTP/1.1 201
Content-type: application/json

{
   "Arn": "string",
   "Id": "string"
}
```

## Response Elements


If the action is successful, the service sends back an HTTP 201 response.

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

 ** [Arn](#API_CreateMulticastGroup_ResponseSyntax) **   <a name="iotwireless-CreateMulticastGroup-response-Arn"></a>
The arn of the multicast group.  
Type: String  
Length Constraints: Maximum length of 128.

 ** [Id](#API_CreateMulticastGroup_ResponseSyntax) **   <a name="iotwireless-CreateMulticastGroup-response-Id"></a>
The ID of the multicast group.  
Type: String  
Length Constraints: Maximum length of 256.

## Errors


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

 ** AccessDeniedException **   
User does not have permission to perform this action.  
HTTP Status Code: 403

 ** ConflictException **   
Adding, updating, or deleting the resource can cause an inconsistent state.    
 ** ResourceId **   
Id of the resource in the conflicting operation.  
 ** ResourceType **   
Type of the resource in the conflicting operation.
HTTP Status Code: 409

 ** InternalServerException **   
An unexpected error occurred while processing a request.  
HTTP Status Code: 500

 ** ResourceNotFoundException **   
Resource does not exist.    
 ** ResourceId **   
Id of the not found resource.  
 ** ResourceType **   
Type of the font found resource.
HTTP Status Code: 404

 ** ThrottlingException **   
The request was denied because it exceeded the allowed API request rate.  
HTTP Status Code: 429

 ** ValidationException **   
The input did not meet the specified constraints.  
HTTP Status Code: 400

## See Also


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/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for .NET V4](https://docs.aws.amazon.com/goto/DotNetSDKV4/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for Go v2](https://docs.aws.amazon.com/goto/SdkForGoV2/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for JavaScript V3](https://docs.aws.amazon.com/goto/SdkForJavaScriptV3/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for Kotlin](https://docs.aws.amazon.com/goto/SdkForKotlin/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for PHP V3](https://docs.aws.amazon.com/goto/SdkForPHPV3/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for Python](https://docs.aws.amazon.com/goto/boto3/iotwireless-2025-11-06/CreateMulticastGroup) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/iotwireless-2025-11-06/CreateMulticastGroup)