WordPress Custom Post Types Development

Developing Custom Post Types for WordPress

WordPress natively works with two content types: "Posts" and "Pages." When a site needs Projects, Vacancies, Real Estate, Reviews, or Products—each gets its own post type (CPT). A CPT provides a separate admin section, custom URLs, archive pages, and full control over data structure. Registering a CPT with basic settings takes a few hours; full setup with URLs, custom columns, and search capabilities takes 1–2 days.

Registration via register_post_type

add_action('init', function () {
    register_post_type('project', [
        'labels' => [
            'name'               => 'Projects',
            'singular_name'      => 'Project',
            'add_new'            => 'Add Project',
            'add_new_item'       => 'New Project',
            'edit_item'          => 'Edit Project',
            'new_item'           => 'New Project',
            'view_item'          => 'View Project',
            'search_items'       => 'Search Projects',
            'not_found'          => 'No projects found',
            'not_found_in_trash' => 'Trash is empty',
            'menu_name'          => 'Projects',
        ],
        'public'             => true,
        'publicly_queryable' => true,
        'show_ui'            => true,
        'show_in_menu'       => true,
        'query_var'          => true,
        'rewrite'            => ['slug' => 'projects', 'with_front' => false],
        'capability_type'    => 'post',
        'has_archive'        => 'projects',
        'hierarchical'       => false,
        'menu_position'      => 5,
        'menu_icon'          => 'dashicons-portfolio',
        'supports'           => ['title', 'editor', 'thumbnail', 'excerpt', 'custom-fields'],
        'show_in_rest'       => true, // required for Gutenberg
        'rest_base'          => 'projects',
    ]);
});

has_archive => 'projects' creates an archive page at /projects/ containing all posts of this type. show_in_rest => true makes the type available via REST API and in the Gutenberg editor.

After registering a new CPT, update rewrite rules: in /wp-admin → Settings → Permalinks click "Save," or programmatically:

register_activation_hook(__FILE__, function () {
    add_action('init', 'register_project_cpt');
    flush_rewrite_rules();
});

Custom Columns in Post List

By default, the project list shows only title and date. Add needed columns:

// Register columns
add_filter('manage_project_posts_columns', function (array $columns): array {
    $new = [];
    foreach ($columns as $key => $title) {
        $new[$key] = $title;
        if ($key === 'title') {
            $new['client']   = 'Client';
            $new['year']     = 'Year';
            $new['featured'] = 'Featured';
        }
    }
    unset($new['comments']);
    return $new;
});

// Display column data
add_action('manage_project_posts_custom_column', function (string $column, int $post_id): void {
    switch ($column) {
        case 'client':
            echo esc_html(get_post_meta($post_id, '_project_client', true) ?: '—');
            break;
        case 'year':
            echo esc_html(get_post_meta($post_id, '_project_year', true) ?: '—');
            break;
        case 'featured':
            $is_featured = get_post_meta($post_id, '_project_featured', true);
            echo $is_featured ? '⭐' : '—';
            break;
    }
}, 10, 2);

// Make column sortable
add_filter('manage_edit-project_sortable_columns', function (array $columns): array {
    $columns['year'] = 'year';
    return $columns;
});

add_action('pre_get_posts', function (WP_Query $query): void {
    if (!is_admin() || !$query->is_main_query()) return;
    if ($query->get('orderby') === 'year') {
        $query->set('meta_key', '_project_year');
        $query->set('orderby', 'meta_value_num');
    }
});

Taxonomy Filter in List

add_action('restrict_manage_posts', function (string $post_type): void {
    if ($post_type !== 'project') return;

    $taxonomy = get_taxonomy('project_category');
    wp_dropdown_categories([
        'taxonomy'         => 'project_category',
        'name'             => 'project_category',
        'show_option_all'  => 'All Categories',
        'selected'         => $_GET['project_category'] ?? 0,
        'value_field'      => 'slug',
        'hierarchical'     => true,
    ]);
});

Including in WordPress Search

By default, WordPress search doesn't include custom CPTs:

add_action('pre_get_posts', function (WP_Query $query): void {
    if ($query->is_search() && !is_admin() && $query->is_main_query()) {
        $post_types = $query->get('post_type') ?: ['post'];
        if (!is_array($post_types)) {
            $post_types = [$post_types];
        }
        $query->set('post_type', array_merge($post_types, ['project', 'vacancy']));
    }
});

Related Posts Between CPTs

The standard way to link two posts is to store the ID in post meta:

// Save relationships
update_post_meta($project_id, '_related_cases', array_map('absint', $case_ids));

// Get related cases
$case_ids = get_post_meta($project_id, '_related_cases', true);
if (!empty($case_ids)) {
    $cases = get_posts([
        'post_type'      => 'case',
        'post__in'       => $case_ids,
        'orderby'        => 'post__in',
        'posts_per_page' => -1,
    ]);
}

For complex two-way relationships (many-to-many), use the Posts 2 Posts plugin or a custom junction table.

CPT vs Taxonomy vs Custom Field

A common mistake is creating a CPT where another tool would be better:

• CPT is needed when an entity has its own pages, archive, and content editor
• Taxonomy is for grouping/filtering (category, tag)
• Custom field is for storing an attribute of an existing post (price, year, address)

Registering a CPT with zero templates and no real content is a waste of structure. If the "type" isn't needed on the frontend—it's probably just a taxonomy for an existing CPT.