Title: pingback_useragent
Published: April 25, 2014
Last modified: February 24, 2026

---

# apply_filters( ‘pingback_useragent’, string $concat_useragent, string $useragent, string $pingback_server_url, string $pagelinkedto, string $pagelinkedfrom )

## In this article

 * [Parameters](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#parameters)
 * [Source](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#changelog)

[ Back to top](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#wp--skip-link--target)

Filters the user agent sent when pinging-back a URL.

## 󠀁[Parameters](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#parameters)󠁿

 `$concat_useragent`string

The user agent concatenated with ‘ — WordPress/’ and the WordPress version.

`$useragent`string

The useragent.

`$pingback_server_url`string

The server URL being linked to.

`$pagelinkedto`string

URL of page linked to.

`$pagelinkedfrom`string

URL of page linked from.

## 󠀁[Source](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#source)󠁿

    ```php
    $client->useragent = apply_filters( 'pingback_useragent', $client->useragent . ' -- WordPress/' . get_bloginfo( 'version' ), $client->useragent, $pingback_server_url, $pagelinkedto, $pagelinkedfrom );
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/comment.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/6.9.4/src/wp-includes/comment.php#L3266)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/comment.php#L3266-L3266)

## 󠀁[Related](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#related)󠁿

| Used by | Description | 
| [pingback()](https://developer.wordpress.org/reference/functions/pingback/)`wp-includes/comment.php` |

Pings back the links found in a post.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/hooks/pingback_useragent/?output_format=md#changelog)󠁿

| Version | Description | 
| [2.9.0](https://developer.wordpress.org/reference/since/2.9.0/) | Introduced. |

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