This is the new *Amazon CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [Amazon CloudFormation User Guide](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/Welcome.html).

# AWS::IoTEvents::AlarmModel Payload
<a name="aws-properties-iotevents-alarmmodel-payload"></a>

Information needed to configure the payload.

By default, Amazon IoT Events generates a standard payload in JSON for any action. This action payload contains all attribute-value pairs that have the information about the detector model instance and the event triggered the action. To configure the action payload, you can use `contentExpression`.

## Syntax
<a name="aws-properties-iotevents-alarmmodel-payload-syntax"></a>

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

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

```
{
  "[ContentExpression](#cfn-iotevents-alarmmodel-payload-contentexpression)" : {{String}},
  "[Type](#cfn-iotevents-alarmmodel-payload-type)" : {{String}}
}
```

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

```
  [ContentExpression](#cfn-iotevents-alarmmodel-payload-contentexpression): {{String}}
  [Type](#cfn-iotevents-alarmmodel-payload-type): {{String}}
```

## Properties
<a name="aws-properties-iotevents-alarmmodel-payload-properties"></a>

`ContentExpression`  <a name="cfn-iotevents-alarmmodel-payload-contentexpression"></a>
The content of the payload. You can use a string expression that includes quoted strings (`'<string>'`), variables (`$variable.<variable-name>`), input values (`$input.<input-name>.<path-to-datum>`), string concatenations, and quoted strings that contain `${}` as the content. The recommended maximum size of a content expression is 1 KB.  
*Required*: Yes  
*Type*: String  
*Minimum*: `1`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Type`  <a name="cfn-iotevents-alarmmodel-payload-type"></a>
The value of the payload type can be either `STRING` or `JSON`.  
*Required*: Yes  
*Type*: String  
*Allowed values*: `STRING | JSON`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)