---
schema_version: "1"
id: 7c81991a26163e8416bb03fe2247fd5997457bd9828775390ad4e7c99e9da6db
title: ConnectApi.Extension
collection: legacydeveloper
version: current
locale: en-us
portal_url: https://docs.salesforce.com/legacydeveloper/current/en-us/apexref/apex_connectapi_output_extension.md
canonical_url: https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_connectapi_output_extension.htm
source_site: developer.salesforce.com
content_type: documentation
content_hash: 28fcaefff26fc3b4527eb70a6b9df48c78af4ce707cfc368068a7b7a40853d88
description: An extension.
---
# ConnectApi.Extension

An extension.

| Property Name | Type | Description | Available Version |
| --- | --- | --- | --- |
| alternative​Representation | [ConnectApi.Alternative](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_connectapi_output_alternative.htm "Alternative representation for an extension on a feed element.") | Alternative representation of the extension. | 40.0 |
| attachmentId | String | Attachment ID of the extension. | 41.0 |
| extensionId | String | ID of the extension. | 40.0 |
| payload | String | Payload associated with the extension. | 40.0 |
| payloadVersion | String | Payload version that identifies the structure of the payload associated with the extension. | 40.0 |

#### See Also

- [ConnectApi.ExtensionsCapability](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_connectapi_output_extensions_capability.htm "If a feed element has this capability, it has one or more extension attachments.")