Title: WP_Speculation_Rules::is_valid_id
Published: April 28, 2025
Last modified: May 20, 2026

---

# WP_Speculation_Rules::is_valid_id( string $id ): bool

## In this article

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

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

This function’s access is marked private. This means it is not intended for use 
by plugin or theme developers, only by core. It is listed here for completeness.

Checks whether the given ID is valid.

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

 `$id`stringrequired

Unique string identifier for the speculation rule.

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

 bool True if the ID is valid, false otherwise.

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

    ```php
    private function is_valid_id( string $id ): bool {
    	return (bool) preg_match( '/^[a-z][a-z0-9_-]+$/', $id );
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/class-wp-speculation-rules.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/7.0/src/wp-includes/class-wp-speculation-rules.php#L254)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/class-wp-speculation-rules.php#L254-L256)

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

| Used by | Description | 
| [WP_Speculation_Rules::add_rule()](https://developer.wordpress.org/reference/classes/wp_speculation_rules/add_rule/)`wp-includes/class-wp-speculation-rules.php` |

Adds a speculation rule to the speculation rules to consider.

  |

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

| Version | Description | 
| [6.8.0](https://developer.wordpress.org/reference/since/6.8.0/) | Introduced. |

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