Title: MimeType::isValid
Published: May 20, 2026

---

# MimeType::isValid( string $mimeType ): bool

## In this article

 * [Parameters](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#parameters)
 * [Return](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#return)
 * [Source](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#source)
 * [Related](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#related)
 * [Changelog](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#changelog)

[ Back to top](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#wp--skip-link--target)

Checks if a MIME type string is valid.

## 󠀁[Parameters](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#parameters)󠁿

 `$mimeType`stringrequired

The MIME type to validate.

## 󠀁[Return](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#return)󠁿

 bool True if valid.

## 󠀁[Source](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#source)󠁿

    ```php
    public static function isValid(string $mimeType): bool
    {
        // Basic MIME type validation: type/subtype
        return (bool) preg_match('/^[a-zA-Z0-9][a-zA-Z0-9!#$&\-\^_+.]*\/[a-zA-Z0-9][a-zA-Z0-9!#$&\-\^_+.]*$/', $mimeType);
    }
    ```

[View all references](https://developer.wordpress.org/reference/files/wp-includes/php-ai-client/src/files/valueobjects/mimetype.php/)
[View on Trac](https://core.trac.wordpress.org/browser/tags/7.0/src/wp-includes/php-ai-client/src/Files/ValueObjects/MimeType.php#L150)
[View on GitHub](https://github.com/WordPress/wordpress-develop/blob/7.0/src/wp-includes/php-ai-client/src/Files/ValueObjects/MimeType.php#L150-L154)

## 󠀁[Related](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#related)󠁿

| Used by | Description | 
| [MimeType::__construct()](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/__construct/)`wp-includes/php-ai-client/src/Files/ValueObjects/MimeType.php` |

Constructor.

  |

## 󠀁[Changelog](https://developer.wordpress.org/reference/classes/wordpress-aiclient-files-valueobjects-mimetype/isvalid/?output_format=md#changelog)󠁿

| Version | Description | 
| [0.1.0](https://developer.wordpress.org/reference/since/0.1.0/) | Introduced. |

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