# CommandPreprocessor
<a name="API_CommandPreprocessor"></a>

Configuration that determines how the `payloadTemplate` is processed by the service to generate the final payload sent to devices at `StartCommandExecution` API invocation.

## Contents
<a name="API_CommandPreprocessor_Contents"></a>

 ** awsJsonSubstitution **   <a name="iot-Type-CommandPreprocessor-awsJsonSubstitution"></a>
Configuration for the JSON substitution preprocessor.  
Type: [AwsJsonSubstitutionCommandPreprocessorConfig](API_AwsJsonSubstitutionCommandPreprocessorConfig.md) object  
Required: No

## See Also
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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/iot-2015-05-28/CommandPreprocessor) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/iot-2015-05-28/CommandPreprocessor) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/iot-2015-05-28/CommandPreprocessor)