Introduce register_content_type() API for declarative content modeling

[whyisjake]

This ticket proposes a new register_content_type() function that provides a higher-level, declarative API for registering custom post types with their associated meta fields in a single call.

Background

Currently, registering a custom post type with structured data requires separate calls to register_post_type() and multiple calls to register_post_meta(). This pattern is verbose, error-prone, and requires developers to manually coordinate REST API schema generation across these separate registrations.

See the full RFC: ​https://docs.google.com/document/d/1Z8ei9vOsj_TvyApq1EKet9BhzA4zdm8uFPd9cXJWpJs/edit

Proposal

Introduce register_content_type() which:

• Registers a post type via register_post_type()
• Registers meta fields via register_post_meta() for each declared field
• Provides automatic REST API schema generation
• Supports field type validation (string, integer, number, boolean, array, object)
• Stores UI hints for potential editor/admin integrations

Example Usage

register_content_type( 'book', array(
    'labels'       => array( 'name' => 'Books' ),
    'public'       => true,
    'show_in_rest' => true,
    'fields'       => array(
        'isbn' => array(
            'type'     => 'string',
            'required' => true,
            'label'    => 'ISBN',
        ),
        'published_year' => array(
            'type'  => 'integer',
            'label' => 'Published Year',
        ),
    ),
) );

New Functions

• register_content_type() / unregister_content_type()
• content_type_exists() / get_content_type_object() / get_content_types()
• get_content_type_fields() / get_content_type_field()
• get_content_type_ui() / get_content_type_rest_schema()
• validate_content_type_values()

Try It

​Live demo in WordPress Playground - includes a "Books" content type with sample data.

Implementation

Pull request: ​https://github.com/WordPress/wordpress-develop/pull/10617

Files added:

• src/wp-includes/class-wp-content-type.php - Core class
• src/wp-includes/content-type.php - API functions
• tests/phpunit/tests/post/wpContentType.php - Unit tests