validate_username() – Function | Developer.WordPress.org

Checks whether a username is valid.

Parameters

$usernamestringrequired: Username.

Return

bool Whether username given is valid.

More Information

This function attempts to sanitize the username, and if it “passes”, the name is considered valid. For additional logic, you can use the ‘validate_username‘ hook.

Source

function validate_username( $username ) {
	$sanitized = sanitize_user( $username, true );
	$valid     = ( $sanitized === $username && ! empty( $sanitized ) );

	/**
	 * Filters whether the provided username is valid.
	 *
	 * @since 2.0.1
	 *
	 * @param bool   $valid    Whether given username is valid.
	 * @param string $username Username to check.
	 */
	return apply_filters( 'validate_username', $valid, $username );
}

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Hooks

apply_filters( ‘validate_username’, bool $valid, string $username ): Filters whether the provided username is valid.

Uses	Description
sanitize_user()`wp-includes/formatting.php`	Sanitizes a username, stripping out unsafe characters.
apply_filters()`wp-includes/plugin.php`	Calls the callback functions that have been added to a filter hook.

Used by	Description
WP_REST_Users_Controller::check_username()`wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php`	Check a username for the REST API.
edit_user()`wp-admin/includes/user.php`	Edit user settings based on contents of $_POST
register_new_user()`wp-includes/user.php`	Handles registering a new user.

Changelog

Version	Description
4.4.0	Empty sanitized usernames are now considered invalid.
2.0.1	Introduced.

User Contributed Notes

Skip to note 2 content

Codex 9 years ago

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Example
```
if ( ! empty( $_POST['username'] ) && validate_username( $_POST['username'] ) ) {
	// Go ahead and save the user...
}
```
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validate_username( string $username ): bool

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