Actions

wp_head is the print slot inside document head. Use it for meta tags and inline snippets — not for enqueueing CSS or JS files.

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Example

add_action( 'wp_head', function() {
    echo '<meta name="theme-color" content="#0073aa">';
} );

Common Use Cases

• Enqueue custom meta tags
• Output inline styles or scripts
• Add Open Graph / SEO tags
• Insert tracking pixels

wp_footer is the last print slot on the front-end. Deferred scripts, analytics, and widgets that must load after content belong here.

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Example

add_action( 'wp_footer', function() {
    echo '<script>console.log("Footer loaded");</script>';
} );

Common Use Cases

• Inject deferred JavaScript
• Add analytics snippets
• Load chat widgets
• Output footer-specific markup

init is the default place to register post types, taxonomies, and rewrite-related APIs. It fires after plugins are loaded and before headers go out.

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Example

add_action( 'init', function() {
    register_post_type( 'book', [
        'public' => true,
        'label'  => 'Books',
    ] );
} );

Common Use Cases

• Register custom post types
• Register custom taxonomies
• Start sessions
• Load text domains (plugins)

Queue front-end CSS and JS here. WordPress prints the tags during wp_head / wp_footer — do not echo link or script tags yourself.

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Example

add_action( 'wp_enqueue_scripts', function() {
    wp_enqueue_style( 'my-style', get_stylesheet_uri() );
    wp_enqueue_script( 'my-script', get_template_directory_uri() . '/js/main.js', [], '1.0', true );
} );

Common Use Cases

• Enqueue theme stylesheet
• Load JavaScript libraries
• Conditionally load assets per page
• Pass PHP data to JS via wp_localize_script
• Migrate off bundled jQuery (deprecated direction in core) toward vanilla JS or a bundler

save_post runs after WordPress writes the post row. Use it for caches, sync, and derived data — and always guard against autosave, revisions, and infinite loops.

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Example

add_action( 'save_post', function( $post_id, $post ) {
    if ( $post->post_type !== 'book' ) {
        return;
    }
    delete_transient( 'book_list_' . $post_id );
}, 10, 2 );

Common Use Cases

• Clear caches after post update
• Send admin email notifications
• Sync data to external APIs
• Auto-generate related records
• Queue heavy sync/recalculation work instead of running it inline on large tables

admin_init is the admin counterpart to init: settings, redirects, and capability checks that must not run on the front-end.

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Example

add_action( 'admin_init', function() {
    register_setting( 'my_options_group', 'my_option_name' );
} );

Common Use Cases

• Register plugin settings
• Redirect non-admin users
• Handle admin form submissions
• Add admin notices conditionally

plugins_loaded is the earliest point where every active plugin's functions and classes are guaranteed to exist — use it for cross-plugin checks, not for registering WordPress objects.

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Example

add_action( 'plugins_loaded', function() {
    if ( class_exists( 'WooCommerce' ) ) {
        require_once __DIR__ . '/integrations/woocommerce.php';
    }
} );

Common Use Cases

• Check if another plugin/class exists
• Load plugin translations
• Bootstrap plugin dependencies
• Set up autoloaders

wp_loaded runs after every init callback has finished — use it when your code depends on things other plugins register on init.

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Example

add_action( 'wp_loaded', function() {
    if ( ! post_type_exists( 'book' ) ) {
        return;
    }
    flush_rewrite_rules();
} );

Common Use Cases

• Read config set by other plugins on init
• Conditional logic that depends on registered post types/taxonomies
• Late-stage bootstrap checks

after_setup_theme is where themes declare support for core features — post thumbnails, menus, HTML5 markup — before WordPress finishes bootstrapping.

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Example

add_action( 'after_setup_theme', function() {
    add_theme_support( 'post-thumbnails' );
    add_theme_support( 'title-tag' );
    register_nav_menus( [ 'primary' => 'Primary Menu' ] );
} );

Common Use Cases

• Declare add_theme_support() features
• Register nav menu locations
• Set content width
• Load theme text domain

widgets_init is exclusively for register_sidebar() and register_widget() calls — nothing else belongs here.

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Example

add_action( 'widgets_init', function() {
    register_sidebar( [
        'name' => 'Footer Widgets',
        'id'   => 'footer-widgets',
        'before_widget' => '<div class="widget %2$s">',
        'after_widget'  => '</div>',
    ] );
} );

Common Use Cases

• Register sidebar/widget areas
• Register custom WP_Widget classes
• Unregister default widgets

admin_enqueue_scripts is the admin equivalent of wp_enqueue_scripts — always check $hook_suffix so you don't load your CSS/JS on every admin screen.

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Example

add_action( 'admin_enqueue_scripts', function( $hook_suffix ) {
    if ( 'post.php' !== $hook_suffix ) {
        return;
    }
    wp_enqueue_script( 'my-admin-js', plugins_url( 'admin.js', __FILE__ ), [ 'jquery' ], '1.0', true );
} );

Common Use Cases

• Enqueue admin CSS/JS scoped to one screen
• Load a color picker or media uploader script
• Pass data to admin JS via wp_localize_script

template_redirect is the standard place to short-circuit a request — custom redirects, maintenance mode, or blocking access — after the query is known but before any template file loads.

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Example

add_action( 'template_redirect', function() {
    if ( is_page( 'old-page' ) ) {
        wp_safe_redirect( home_url( '/new-page/' ), 301 );
        exit;
    }
} );

Common Use Cases

• Custom redirects based on conditional tags
• Block access / maintenance mode
• Serve a custom response instead of a template (e.g. JSON)
• Force login on specific pages

pre_get_posts fires for every query — main and secondary. Always check is_main_query() (and is_admin()) or you'll silently break widgets, related-post queries, and REST requests.

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Example

add_action( 'pre_get_posts', function( $query ) {
    if ( ! is_admin() && $query->is_main_query() && is_post_type_archive( 'book' ) ) {
        $query->set( 'posts_per_page', 24 );
    }
} );

Common Use Cases

• Change posts_per_page for an archive
• Include/exclude post types from search
• Reorder posts on a custom query
• Restrict a query by taxonomy or meta

wp_insert_post looks like save_post but fires from every wp_insert_post() call, including programmatic inserts that never touch the block editor.

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Example

add_action( 'wp_insert_post', function( $post_id, $post, $update ) {
    if ( 'book' !== $post->post_type || $update ) {
        return;
    }
    wp_mail( get_option( 'admin_email' ), 'New book added', get_the_title( $post_id ) );
}, 10, 3 );

Common Use Cases

• Notify on new post creation (not updates)
• React to programmatic/import inserts
• Sync newly created posts to an external system

transition_post_status is the only hook that reliably tells you a status changed — including the old value — which save_post cannot do.

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Example

add_action( 'transition_post_status', function( $new_status, $old_status, $post ) {
    if ( 'publish' === $new_status && 'publish' !== $old_status ) {
        wp_mail( get_option( 'admin_email' ), 'Post published', get_the_title( $post ) );
    }
}, 10, 3 );

Common Use Cases

• Detect draft-to-publish transitions
• Log status change history
• Trigger workflows on unpublish/trash
• Build scheduled-publish notifications

admin_menu is exclusively for add_menu_page() / add_submenu_page() calls; anything else belongs on admin_init.

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Example

add_action( 'admin_menu', function() {
    add_menu_page( 'My Plugin', 'My Plugin', 'manage_options', 'my-plugin', 'my_plugin_render_page', 'dashicons-admin-generic', 66 );
} );

Common Use Cases

• Register top-level or submenu admin pages
• Remove default menu items for non-admins
• Reorder menu items

admin_notices runs on every admin screen — always check current_user_can() or a specific screen ID so your notice doesn't nag every user on every page.

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Example

add_action( 'admin_notices', function() {
    if ( ! current_user_can( 'manage_options' ) ) {
        return;
    }
    echo '<div class="notice notice-warning"><p>Please configure My Plugin.</p></div>';
} );

Common Use Cases

• Show setup/configuration warnings
• Confirm a settings save succeeded
• Prompt for a plugin update or license key
• Surface validation errors after form submit

wp_login fires only on a successful authentication — pair it with wp_login_failed to cover both outcomes.

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Example

add_action( 'wp_login', function( $user_login, $user ) {
    update_user_meta( $user->ID, 'last_login', current_time( 'mysql' ) );
}, 10, 2 );

Common Use Cases

• Track last login time
• Redirect users by role after login
• Log login events for security auditing
• Trigger welcome logic on first login

user_register fires right after wp_insert_user() writes the row — the account exists but you're still inside the registration request, which matters for redirects and emails.

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Example

add_action( 'user_register', function( $user_id ) {
    $user = new WP_User( $user_id );
    $user->set_role( 'subscriber' );
    wp_mail( $user->user_email, 'Welcome!', 'Thanks for registering.' );
} );

Common Use Cases

• Send welcome emails
• Assign a default role
• Sync new users to a CRM/mailing list
• Set default user meta on signup

rest_api_init is the register_rest_route() equivalent of init — it only fires on REST requests, not every page load.

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Example

add_action( 'rest_api_init', function() {
    register_rest_route( 'my-plugin/v1', '/books', [
        'methods'  => 'GET',
        'callback' => 'my_plugin_get_books',
        'permission_callback' => '__return_true',
    ] );
} );

Common Use Cases

• Register custom REST routes
• Expose extra fields on existing endpoints via register_rest_field
• Add custom REST authentication logic

wp_logout is the mirror of wp_login — use it to clear per-user cookies, caches, or add custom redirect logic.

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Example

add_action( 'wp_logout', function( $user_id ) {
    delete_transient( 'user_session_' . $user_id );
} );

Common Use Cases

• Clear custom cookies or transients on logout
• Log a security/audit event
• Redirect to a custom page after logout
• Invalidate a cached per-user fragment

comment_post fires right after a new comment saves — the standard place to trigger notifications or moderation logic.

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Example

add_action( 'comment_post', function( $comment_id, $approved ) {
    if ( 1 === $approved ) {
        wp_mail( get_option( 'admin_email' ), 'New comment', 'A comment was just approved.' );
    }
}, 10, 2 );

Common Use Cases

• Send custom notification emails
• Auto-flag suspicious comments for review
• Sync comments to an external system
• Award points/badges for commenting

wp_insert_comment is the lower-level sibling of comment_post — it fires for every comment insert, including ones triggered programmatically, not just front-end submissions.

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Example

add_action( 'wp_insert_comment', function( $id, $comment ) {
    error_log( 'New comment #' . $id . ' on post ' . $comment->comment_post_ID );
}, 10, 2 );

Common Use Cases

• React to comments created via REST API or import scripts, not just the comment form
• Sync a WP_Comment object right after creation
• Trigger downstream logic that needs the full comment object rather than raw array data

enqueue_block_editor_assets is the block-editor-only counterpart to wp_enqueue_scripts — it never runs on the public front-end.

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Example

add_action( 'enqueue_block_editor_assets', function() {
    wp_enqueue_script(
        'my-block-editor-script',
        get_template_directory_uri() . '/js/editor.js',
        [ 'wp-blocks', 'wp-element', 'wp-editor' ],
        '1.0'
    );
} );

Common Use Cases

• Load custom block registration JS
• Add editor-only CSS for custom blocks
• Register a Gutenberg sidebar plugin
• Load third-party editor extensions

before_delete_post is your last chance to act while the post (and its data) still exists — right after this, wp_delete_post() removes the row for good.

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Example

add_action( 'before_delete_post', function( $post_id, $post ) {
    if ( 'book' !== $post->post_type ) {
        return;
    }
    global $wpdb;
    $wpdb->delete( $wpdb->prefix . 'book_ratings', [ 'post_id' => $post_id ] );
}, 10, 2 );

Common Use Cases

• Clean up custom database rows tied to a post
• Delete associated generated/uploaded files
• Sync the deletion to an external system
• Log permanent deletions for an audit trail

enqueue_block_assets is the one enqueue hook that runs in both places — the block editor and the public front-end — making it the right spot for a block's own shared styling.

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Example

add_action( 'enqueue_block_assets', function() {
    wp_enqueue_style( 'my-block-style', get_template_directory_uri() . '/css/block.css' );
} );

Common Use Cases

• Load a custom block's CSS so it looks right in the editor and on the front-end
• Share fonts/variables between editor preview and rendered output
• Avoid duplicating enqueue code across wp_enqueue_scripts and enqueue_block_editor_assets