---
schema_version: "1"
id: c19a5781a70a3f9122cc76cf09a117e5ce6449c678ab5dcb96a8d76be44fd3f3
title: AuthenticatedMemberID()
collection: developer
version: current
locale: en-us
portal_url: https://docs.salesforce.com/developer/current/en-us/marketing-cloud/ampscript/references/sites/mc-ampscript-reference-sites-authenticated-member-id.md
canonical_url: https://developer.salesforce.com/docs/marketing/marketing-cloud-ampscript/references/mc-ampscript-sites/mc-ampscript-reference-sites-authenticated-member-id.html
source_site: developer.salesforce.com
content_type: documentation
content_hash: 5d9a35faca0b7e0252e3302f111d9ea4c5c98059eae830b487edeb6e09220c55
products:
  - AMPscript for Marketing Cloud
  - Marketing Cloud
---
# AuthenticatedMemberID()

Returns the member ID of the authenticated landing page user. Use this function only with Microsites when using Sender Authenticated Redirection. Not for use with CloudPages.

## Availability

<table>
  <tr>
    <td>Marketing Cloud Engagement</td>
    <td>✅ Yes</td>
  </tr>
  <tr>
    <td>Marketing Cloud Next</td>
    <td>❌ No</td>
  </tr>
</table>

## Syntax

The `AuthenticatedMemberID()` function doesn’t accept any parameters.

## Usage

You can call this function without passing any parameters.

```
%%[ Output(AuthenticatedMemberID()) ]%%
```

The example outputs the member ID for the authenticated landing page user.