Code Snippet to Add Custom Taxonomies for Organizing Content in WordPress

Custom Taxonomy Implementation

Basic Solution

Here's a code snippet to create a custom taxonomy. Place this in your theme's functions.php file or in a site-specific plugin:

This code creates a custom taxonomy called "Genre" for posts:

function create_genre_taxonomy() {
    register_taxonomy(
        'genre',
        'post',
        array(
            'labels' => array(
                'name' => 'Genres',
                'singular_name' => 'Genre',
                'menu_name' => 'Genres',
                'add_new_item' => 'Add New Genre',
                'new_item_name' => 'New Genre Name'
            ),
            'hierarchical' => true,
            'show_ui' => true,
            'show_admin_column' => true,
            'query_var' => true,
            'rewrite' => array('slug' => 'genre'),
            'show_in_rest' => true
        )
    );
}
add_action('init', 'create_genre_taxonomy');

Advanced Solution

This extended version creates a custom taxonomy for multiple post types with additional features:

function register_custom_taxonomies() {
    // Book Genre Taxonomy
    $labels = array(
        'name' => 'Genres',
        'singular_name' => 'Genre',
        'menu_name' => 'Genres',
        'all_items' => 'All Genres',
        'edit_item' => 'Edit Genre',
        'view_item' => 'View Genre',
        'update_item' => 'Update Genre',
        'add_new_item' => 'Add New Genre',
        'new_item_name' => 'New Genre Name',
        'search_items' => 'Search Genres',
        'popular_items' => 'Popular Genres',
        'separate_items_with_commas' => 'Separate genres with commas',
        'choose_from_most_used' => 'Choose from most used genres',
        'not_found' => 'No genres found'
    );

    $args = array(
        'labels' => $labels,
        'hierarchical' => true,
        'public' => true,
        'show_ui' => true,
        'show_admin_column' => true,
        'show_in_nav_menus' => true,
        'show_tagcloud' => true,
        'show_in_rest' => true,
        'query_var' => true,
        'rewrite' => array('slug' => 'genre'),
        'capabilities' => array(
            'manage_terms' => 'manage_categories',
            'edit_terms' => 'manage_categories',
            'delete_terms' => 'manage_categories',
            'assign_terms' => 'edit_posts'
        )
    );

    register_taxonomy('genre', array('post', 'book'), $args);
}
add_action('init', 'register_custom_taxonomies');

Usage Notes

• Replace 'genre' with your desired taxonomy name
• Modify 'post' or array('post', 'book') to specify which post types should use this taxonomy
• Set 'hierarchical' to true for category-like behavior or false for tag-like behavior
• 'show_in_rest' enables Gutenberg editor support

Plugin Alternatives

If you prefer a plugin solution:

1. Custom Post Type UI - User-friendly interface for creating custom taxonomies
2. Pods - Advanced content type and field management
3. Toolset Types - Professional solution for custom content structures

Important Considerations

• After creating a new taxonomy, visit Settings > Permalinks to refresh rewrite rules
• Custom taxonomies can improve SEO by creating more specific content organization
• Use meaningful taxonomy names that reflect your content structure
• Consider URL structure when setting the 'rewrite' slug