# CloudFormation template Outputs syntax
<a name="outputs-section-structure"></a>

The optional `Outputs` section declares output values for the stack. These output values can be used in various ways:
+ **Capture important details about your resources** – An output is a convenient way to capture important information about your resources. For example, you can output the S3 bucket name for a stack to make the bucket easier to find. You can view output values in the **Outputs** tab of the CloudFormation console or by using the [describe-stacks](service_code_examples.md#describe-stacks-sdk) CLI command. 
+ **Cross-stack references** – You can import output values into other stacks to [create references between stacks](using-cfn-stack-exports.md). This is helpful when you need to share resources or configurations across multiple stacks.

**Important**  
CloudFormation doesn't redact or obfuscate any information you include in the `Outputs` section. We strongly recommend you don't use this section to output sensitive information, such as passwords or secrets.  
Output values are available after the stack operation is complete. Stack output values aren't available when a stack status is in any of the `IN_PROGRESS` [statuses](view-stack-events.md#cfn-console-view-stack-data-resources-status-codes). We don't recommend establishing dependencies between a service runtime and the stack output value because output values might not be available at all times.

## Syntax
<a name="outputs-section-syntax"></a>

The `Outputs` section consists of the key name `Outputs`. You can declare a maximum of 200 outputs in a template.

The following example demonstrates the structure of the `Outputs` section.

### JSON
<a name="outputs-section-structure-syntax.json"></a>

Use braces to enclose all output declarations. Delimit multiple outputs with commas.

```
"Outputs" : {
  "OutputLogicalID" : {
    "Description" : "Information about the value",
    "Value" : "Value to return",
    "Export" : {
      "Name" : "Name of resource to export"
    }
  }
}
```

### YAML
<a name="outputs-section-structure-syntax.yaml"></a>

```
Outputs:
  OutputLogicalID:
    Description: Information about the value
    Value: Value to return
    Export:
      Name: Name of resource to export
```

### Output fields
<a name="outputs-section-structure-output-fields"></a>

The `Outputs` section can include the following fields.

**Logical ID (also called *logical name*)**  
An identifier for the current output. The logical ID must be alphanumeric (`a–z`, `A–Z`, `0–9`) and unique within the template.

**`Description` (optional)**  
A `String` type that describes the output value. The value for the description declaration must be a literal string that's between 0 and 1024 bytes in length. You can't use a parameter or function to specify the description. 

**`Value` (required)**  
The value of the property returned by the [describe-stacks](service_code_examples.md#describe-stacks-sdk) command. The value of an output can include literals, parameter references, pseudo parameters, a mapping value, or intrinsic functions.

**`Export` (optional)**  
The name of the resource output to be exported for a cross-stack reference.  
You can use intrinsic functions to customize the `Name` value of an export.  
For more information, see [Get exported outputs from a deployed CloudFormation stack](using-cfn-stack-exports.md).

To associate a condition with an output, define the condition in the [Conditions](conditions-section-structure.md) section of the template.

## Examples
<a name="outputs-section-structure-examples"></a>

The following examples illustrate how stack output works.

**Topics**
+ [Stack output](#outputs-section-structure-examples-stack-output)
+ [Customize export name using `Fn::Sub`](#outputs-section-structure-examples-cross-stack)
+ [Customize export name using `Fn::Join`](#outputs-section-structure-examples-join-export-name)
+ [Return a URL constructed using `Fn::Join`](#outputs-section-structure-examples-join-export-url)

### Stack output
<a name="outputs-section-structure-examples-stack-output"></a>

In the following example, the output named `BackupLoadBalancerDNSName` returns the DNS name for the resource with the logical ID `BackupLoadBalancer` only when the `CreateProdResources` condition is true. The output named `InstanceID` returns the ID of the EC2 instance with the logical ID `EC2Instance`.

#### JSON
<a name="outputs-section-structure-example.json"></a>

```
"Outputs" : {
  "BackupLoadBalancerDNSName" : {
    "Description": "The DNSName of the backup load balancer",  
    "Value" : { "Fn::GetAtt" : [ "BackupLoadBalancer", "DNSName" ]},
    "Condition" : "CreateProdResources"
  },
  "InstanceID" : {
    "Description": "The Instance ID",  
    "Value" : { "Ref" : "EC2Instance" }
  }
}
```

#### YAML
<a name="outputs-section-structure-example.yaml"></a>

```
Outputs:
  BackupLoadBalancerDNSName:
    Description: The DNSName of the backup load balancer
    Value: !GetAtt BackupLoadBalancer.DNSName
    Condition: CreateProdResources
  InstanceID:
    Description: The Instance ID
    Value: !Ref EC2Instance
```

### Customize export name using `Fn::Sub`
<a name="outputs-section-structure-examples-cross-stack"></a>

In the following examples, the output named `StackVPC` returns the ID of a VPC, and then exports the value for cross-stack referencing with the name `VPCID` appended to the stack's name.

#### JSON
<a name="outputs-section-structure-cross-stack-example.json"></a>

```
"Outputs" : {
  "StackVPC" : {
    "Description" : "The ID of the VPC",
    "Value" : { "Ref" : "MyVPC" },
    "Export" : {
      "Name" : {"Fn::Sub": "${AWS::StackName}-VPCID" }
    }
  }
}
```

#### YAML
<a name="outputs-section-structure-cross-stack-example.yaml"></a>

```
Outputs:
  StackVPC:
    Description: The ID of the VPC
    Value: !Ref MyVPC
    Export:
      Name: !Sub "${AWS::StackName}-VPCID"
```

For more information about the `Fn::Sub` function, see [https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-sub.html](https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-sub.html).

### Customize export name using `Fn::Join`
<a name="outputs-section-structure-examples-join-export-name"></a>

You can also use the `Fn::Join` function to construct values based on parameters, resource attributes, and other strings.

The following examples use the `Fn::Join` function to customize the export name instead of the `Fn::Sub` function. The example `Fn::Join` function concatenates the stack name with the name `VPCID` using a colon as a separator.

#### JSON
<a name="outputs-section-structure-join-export-name-example.json"></a>

```
"Outputs" : {
  "StackVPC" : {
    "Description" : "The ID of the VPC",
    "Value" : { "Ref" : "MyVPC" },
    "Export" : {
      "Name" : { "Fn::Join" : [ ":", [ { "Ref" : "AWS::StackName" }, "VPCID" ] ] }
    }
  }
}
```

#### YAML
<a name="outputs-section-structure-join-export-name-example.yaml"></a>

```
Outputs:
  StackVPC:
    Description: The ID of the VPC
    Value: !Ref MyVPC
    Export:
      Name: !Join [ ":", [ !Ref "AWS::StackName", VPCID ] ]
```

For more information about the `Fn::Join` function, see [https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-join.html](https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-join.html).

### Return a URL constructed using `Fn::Join`
<a name="outputs-section-structure-examples-join-export-url"></a>

In the following example for a template that creates a WordPress site, `InstallURL` is the string returned by a `Fn::Join` function call that concatenates `http://`, the DNS name of the resource `ElasticLoadBalancer`, and `/wp-admin/install.php`. The output value would be similar to the following:

```
http://mywptests-elasticl-1gb51l6sl8y5v-206169572.aws-region.elb.amazonaws.com/wp-admin/install.php
```

#### JSON
<a name="outputs-section-structure-examples-join-export-url.json"></a>

```
{
    "Outputs": {
        "InstallURL": {
            "Value": {
                "Fn::Join": [
                    "",
                    [
                        "http://",
                        {
                            "Fn::GetAtt": [
                                "ElasticLoadBalancer",
                                "DNSName"
                            ]
                        },
                        "/wp-admin/install.php"
                    ]
                ]
            },
            "Description": "Installation URL of the WordPress website"
        }
    }
}
```

#### YAML
<a name="outputs-section-structure-examples-join-export-url.yaml"></a>

```
Outputs:
  InstallURL:
    Value: !Join 
      - ''
      - - 'http://'
        - !GetAtt 
          - ElasticLoadBalancer
          - DNSName
        - /wp-admin/install.php
    Description: Installation URL of the WordPress website
```

For more information about the `Fn::Join` function, see [https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-join.html](https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/intrinsic-function-reference-join.html).