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# AWS::IoTEvents::Input InputDefinition
<a name="aws-properties-iotevents-input-inputdefinition"></a>

The definition of the input.

## Syntax
<a name="aws-properties-iotevents-input-inputdefinition-syntax"></a>

To declare this entity in your CloudFormation template, use the following syntax:

### JSON
<a name="aws-properties-iotevents-input-inputdefinition-syntax.json"></a>

```
{
  "[Attributes](#cfn-iotevents-input-inputdefinition-attributes)" : [ Attribute, ... ]
}
```

### YAML
<a name="aws-properties-iotevents-input-inputdefinition-syntax.yaml"></a>

```
  [Attributes](#cfn-iotevents-input-inputdefinition-attributes): 
    - Attribute
```

## Properties
<a name="aws-properties-iotevents-input-inputdefinition-properties"></a>

`Attributes`  <a name="cfn-iotevents-input-inputdefinition-attributes"></a>
The attributes from the JSON payload that are made available by the input. Inputs are derived from messages sent to the AWS IoT Events system using `BatchPutMessage`. Each such message contains a JSON payload, and those attributes (and their paired values) specified here are available for use in the `condition` expressions used by detectors that monitor this input.   
*Required*: Yes  
*Type*: Array of [Attribute](aws-properties-iotevents-input-attribute.md)  
*Minimum*: `1`  
*Maximum*: `200`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)