# IotTopicPublishAction


Information required to publish the MQTT message through the AWS IoT message broker.

## Contents


 ** mqttTopic **   <a name="iotevents-Type-IotTopicPublishAction-mqttTopic"></a>
The MQTT topic of the message. You can use a string expression that includes variables (`$variable.<variable-name>`) and input values (`$input.<input-name>.<path-to-datum>`) as the topic string.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Required: Yes

 ** payload **   <a name="iotevents-Type-IotTopicPublishAction-payload"></a>
You can configure the action payload when you publish a message to an AWS IoT Core topic.  
Type: [Payload](API_Payload.md) object  
Required: No

## See Also


For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/iotevents-2018-07-27/IotTopicPublishAction) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/iotevents-2018-07-27/IotTopicPublishAction) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/iotevents-2018-07-27/IotTopicPublishAction)