Title: add_site_meta
Published: February 22, 2019
Last modified: May 20, 2026

---

# add_site_meta( int $site_id, string $meta_key, mixed $meta_value, bool $unique = false ): int|false

## In this article

 * [Description](https://developer.wordpress.org/reference/functions/add_site_meta/?output_format=md#description)
 * [Parameters](https://developer.wordpress.org/reference/functions/add_site_meta/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/functions/add_site_meta/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/functions/add_site_meta/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/functions/add_site_meta/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/functions/add_site_meta/?output_format=md#changelog)

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

Adds metadata to a site.

## 󠀁[Description](https://developer.wordpress.org/reference/functions/add_site_meta/?output_format=md#description)󠁿

For historical reasons both the meta key and the meta value are expected to be “
slashed” (slashes escaped) on input.

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

 `$site_id`intrequired

Site ID.

`$meta_key`stringrequired

Metadata name.

`$meta_value`mixedrequired

Metadata value. Arrays and objects are stored as serialized data and will be returned
as the same type when retrieved. Other data types will be stored as strings in the
database:

 * false is stored and retrieved as an empty string (`''`)
 * true is stored and retrieved as `'1'`
 * numbers (both integer and float) are stored and retrieved as strings Must be 
   serializable if non-scalar.

`$unique`booloptional

Whether the same key should not be added.

Default:`false`

## 󠀁[Return](https://developer.wordpress.org/reference/functions/add_site_meta/?output_format=md#return)󠁿

 int|false Meta ID on success, false on failure.

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

    ```php
    function add_site_meta( $site_id, $meta_key, $meta_value, $unique = false ) {
    	return add_metadata( 'blog', $site_id, $meta_key, $meta_value, $unique );
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/ms-site.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/7.0/src/wp-includes/ms-site.php#L1042)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/ms-site.php#L1042-L1044)

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

| Uses | Description | 
| [add_metadata()](https://developer.wordpress.org/reference/functions/add_metadata/)`wp-includes/meta.php` |

Adds metadata for the specified object.

  |

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

| Version | Description | 
| [5.1.0](https://developer.wordpress.org/reference/since/5.1.0/) | Introduced. |

## User Contributed Notes

You must [log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fdeveloper.wordpress.org%2Freference%2Ffunctions%2Fadd_site_meta%2F)
before being able to contribute a note or feedback.