init │ action-hook │ WP 1.5.0

Fires after WordPress has finished loading but before any HTTP headers are sent.

init is a popular event. Plugins commonly use it to initialize themselves. This hook is useful for many reasons: for example, when the user must already be identified, taxonomies are needed, or functions defined by the theme (functions.php or another file) are required.

By the time init fires, the current user is authenticated (the global $current_user is already defined), and all main WordPress global variables and functions are set up. Theme functions are also loaded, and settings such as thumbnail sizes and menu support have been registered.

You can use wp_loaded instead of init; the events are nearly identical. wp_loaded fires immediately after init and after ms_site_check() checks the current blog in a multisite installation. wp_loaded does not fire if the current blog fails its operational check (it is inactive, deleted, marked as spam, or archived).

Events that fire before init:

muplugins_loaded
registered_taxonomy
registered_post_type
plugins_loaded
sanitize_comment_cookies
setup_theme
load_textdomain
after_setup_theme
auth_cookie_malformed
auth_cookie_valid
set_current_user
init

Usage

add_action( 'init', 'wp_kama_init_action' );

/**
 * Function for `init` action-hook.
 * 
 * @return void
 */
function wp_kama_init_action(){

	// action...
}

Examples

#1 Attach to other events from init

add_action('init','all_my_hooks');
function all_my_hooks(){
	// Attach handlers to later events.
	add_action('admin_init', 'my_function_name');
	add_action('admin_menu', 'my_function_name');
}

#2 Handle a `$_GET` request

Suppose we need to redirect to the registration page when the request contains the register variable:

add_action('init', 'redirect_to_register');
function redirect_to_register(){
	if( isset( $_GET['register'] ) ) {
		wp_redirect( site_url() . 'wp-register.php');
		exit;
	}
}

Changelog

Since 1.5.0

Introduced.

Where the hook is called

In file: /wp-settings.php

enable_loading_advanced_cache_dropin

mu_plugin_loaded

network_plugin_loaded

muplugins_loaded

plugin_loaded

plugins_loaded

sanitize_comment_cookies

init

do_action( 'init' );

Where the hook is used in WordPress

wp-includes/block-bindings/pattern-overrides.php 47

add_action( 'init', '_register_block_bindings_pattern_overrides_source' );

wp-includes/block-bindings/post-data.php 98

add_action( 'init', '_register_block_bindings_post_data_source' );

wp-includes/block-bindings/post-meta.php 70

add_action( 'init', '_register_block_bindings_post_meta_source' );

wp-includes/block-bindings/term-data.php 119

add_action( 'init', '_register_block_bindings_term_data_source' );

wp-includes/block-patterns.php 478

add_action( 'init', '_register_theme_block_patterns' );

wp-includes/block-supports/custom-css.php 330

add_action( 'init', 'wp_custom_css_kses_init', 20 );

wp-includes/blocks/accordion-item.php 87

add_action( 'init', 'register_block_core_accordion_item' );

wp-includes/blocks/accordion.php 45

add_action( 'init', 'register_block_core_accordion' );

wp-includes/blocks/archives.php 174

add_action( 'init', 'register_block_core_archives' );

wp-includes/blocks/avatar.php 166

add_action( 'init', 'register_block_core_avatar' );

wp-includes/blocks/block.php 107

add_action( 'init', 'register_block_core_block' );

wp-includes/blocks/breadcrumbs.php 611

add_action( 'init', 'register_block_core_breadcrumbs' );

wp-includes/blocks/button.php 147

add_action( 'init', 'register_block_core_button' );

wp-includes/blocks/calendar.php 96

add_action( 'init', 'register_block_core_calendar' );

wp-includes/blocks/categories.php 159

add_action( 'init', 'register_block_core_categories' );

wp-includes/blocks/comment-author-name.php 69

add_action( 'init', 'register_block_core_comment_author_name' );

wp-includes/blocks/comment-content.php 85

add_action( 'init', 'register_block_core_comment_content' );

wp-includes/blocks/comment-date.php 64

add_action( 'init', 'register_block_core_comment_date' );

wp-includes/blocks/comment-edit-link.php 65

add_action( 'init', 'register_block_core_comment_edit_link' );

wp-includes/blocks/comment-reply-link.php 87

add_action( 'init', 'register_block_core_comment_reply_link' );

wp-includes/blocks/comment-template.php 153

add_action( 'init', 'register_block_core_comment_template' );

wp-includes/blocks/comments-pagination-next.php 64

add_action( 'init', 'register_block_core_comments_pagination_next' );

wp-includes/blocks/comments-pagination-numbers.php 66

add_action( 'init', 'register_block_core_comments_pagination_numbers' );

wp-includes/blocks/comments-pagination-previous.php 57

add_action( 'init', 'register_block_core_comments_pagination_previous' );

wp-includes/blocks/comments-pagination.php 55

add_action( 'init', 'register_block_core_comments_pagination' );

wp-includes/blocks/comments-title.php 100

add_action( 'init', 'register_block_core_comments_title' );

wp-includes/blocks/comments.php 102

add_action( 'init', 'register_block_core_comments' );

wp-includes/blocks/comments.php 227

add_action( 'init', 'register_legacy_post_comments_block', 21 );

wp-includes/blocks/cover.php 215

add_action( 'init', 'register_block_core_cover' );

wp-includes/blocks/details.php 47

add_action( 'init', 'register_block_core_details' );

wp-includes/blocks/file.php 67

add_action( 'init', 'register_block_core_file' );

wp-includes/blocks/footnotes.php 113

add_action( 'init', 'register_block_core_footnotes_post_meta', 20 );

wp-includes/blocks/footnotes.php 78

add_action( 'init', 'register_block_core_footnotes' );

wp-includes/blocks/gallery.php 588

add_action( 'init', 'register_block_core_gallery' );

wp-includes/blocks/heading.php 56

add_action( 'init', 'register_block_core_heading' );

wp-includes/blocks/home-link.php 157

add_action( 'init', 'register_block_core_home_link' );

wp-includes/blocks/icon.php 146

add_action( 'init', 'register_block_core_icon' );

wp-includes/blocks/image.php 420

add_action( 'init', 'register_block_core_image' );

wp-includes/blocks/index.php 144

add_action( 'init', 'register_core_block_style_handles', 9 );

wp-includes/blocks/index.php 160

add_action( 'init', 'register_core_block_types_from_metadata' );

wp-includes/blocks/index.php 177

add_action( 'init', 'wp_register_core_block_metadata_collection', 9 );

wp-includes/blocks/latest-comments.php 174

add_action( 'init', 'register_block_core_latest_comments' );

wp-includes/blocks/latest-posts.php 283

add_action( 'init', 'register_block_core_latest_posts' );

wp-includes/blocks/legacy-widget.php 73

add_action( 'init', 'register_block_core_legacy_widget' );

wp-includes/blocks/list.php 54

add_action( 'init', 'register_block_core_list' );

wp-includes/blocks/loginout.php 74

add_action( 'init', 'register_block_core_loginout' );

wp-includes/blocks/media-text.php 131

add_action( 'init', 'register_block_core_media_text' );

wp-includes/blocks/navigation-link.php 504

add_action( 'init', 'register_block_core_navigation_link' );

wp-includes/blocks/navigation-overlay-close.php 56

add_action( 'init', 'register_block_core_navigation_overlay_close' );

wp-includes/blocks/navigation-submenu.php 320

add_action( 'init', 'register_block_core_navigation_submenu' );

wp-includes/blocks/navigation.php 1597

add_action( 'init', 'register_block_core_navigation' );

wp-includes/blocks/page-list-item.php 16

add_action( 'init', 'register_block_core_page_list_item' );

wp-includes/blocks/page-list.php 367

add_action( 'init', 'register_block_core_page_list' );

wp-includes/blocks/paragraph.php 48

add_action( 'init', 'register_block_core_paragraph' );

wp-includes/blocks/pattern.php 72

add_action( 'init', 'register_block_core_pattern' );

wp-includes/blocks/playlist-track.php 81

add_action( 'init', 'register_block_core_playlist_track' );

wp-includes/blocks/playlist.php 210

add_action( 'init', 'register_block_core_playlist' );

wp-includes/blocks/post-author-biography.php 53

add_action( 'init', 'register_block_core_post_author_biography' );

wp-includes/blocks/post-author-name.php 63

add_action( 'init', 'register_block_core_post_author_name' );

wp-includes/blocks/post-author.php 81

add_action( 'init', 'register_block_core_post_author' );

wp-includes/blocks/post-comments-count.php 49

add_action( 'init', 'register_block_core_post_comments_count' );

wp-includes/blocks/post-comments-form.php 70

add_action( 'init', 'register_block_core_post_comments_form' );

wp-includes/blocks/post-comments-link.php 75

add_action( 'init', 'register_block_core_post_comments_link' );

wp-includes/blocks/post-content.php 96

add_action( 'init', 'register_block_core_post_content' );

wp-includes/blocks/post-date.php 106

add_action( 'init', 'register_block_core_post_date' );

wp-includes/blocks/post-excerpt.php 96

add_action( 'init', 'register_block_core_post_excerpt' );

wp-includes/blocks/post-featured-image.php 272

add_action( 'init', 'register_block_core_post_featured_image' );

wp-includes/blocks/post-navigation-link.php 139

add_action( 'init', 'register_block_core_post_navigation_link' );

wp-includes/blocks/post-template.php 165

add_action( 'init', 'register_block_core_post_template' );

wp-includes/blocks/post-terms.php 130

add_action( 'init', 'register_block_core_post_terms' );

wp-includes/blocks/post-time-to-read.php 185

add_action( 'init', 'register_block_core_post_time_to_read' );

wp-includes/blocks/post-title.php 74

add_action( 'init', 'register_block_core_post_title' );

wp-includes/blocks/query-no-results.php 65

add_action( 'init', 'register_block_core_query_no_results' );

wp-includes/blocks/query-pagination-next.php 102

add_action( 'init', 'register_block_core_query_pagination_next' );

wp-includes/blocks/query-pagination-numbers.php 133

add_action( 'init', 'register_block_core_query_pagination_numbers' );

wp-includes/blocks/query-pagination-previous.php 95

add_action( 'init', 'register_block_core_query_pagination_previous' );

wp-includes/blocks/query-pagination.php 51

add_action( 'init', 'register_block_core_query_pagination' );

wp-includes/blocks/query-title.php 103

add_action( 'init', 'register_block_core_query_title' );

wp-includes/blocks/query-total.php 90

add_action( 'init', 'register_block_core_query_total' );

wp-includes/blocks/query.php 71

add_action( 'init', 'register_block_core_query' );

wp-includes/blocks/read-more.php 63

add_action( 'init', 'register_block_core_read_more' );

wp-includes/blocks/rss.php 145

add_action( 'init', 'register_block_core_rss' );

wp-includes/blocks/search.php 240

add_action( 'init', 'register_block_core_search' );

wp-includes/blocks/shortcode.php 35

add_action( 'init', 'register_block_core_shortcode' );

wp-includes/blocks/site-logo.php 119

add_action( 'init', 'register_block_core_site_logo' );

wp-includes/blocks/site-tagline.php 53

add_action( 'init', 'register_block_core_site_tagline' );

wp-includes/blocks/site-title.php 69

add_action( 'init', 'register_block_core_site_title' );

wp-includes/blocks/social-link.php 89

add_action( 'init', 'register_block_core_social_link' );

wp-includes/blocks/tab-list.php 76

add_action( 'init', 'register_block_core_tab_list' );

wp-includes/blocks/tab-panel.php 65

add_action( 'init', 'register_block_core_tab_panel' );

wp-includes/blocks/tabs.php 139

add_action( 'init', 'register_block_core_tabs' );

wp-includes/blocks/tag-cloud.php 63

add_action( 'init', 'register_block_core_tag_cloud' );

wp-includes/blocks/template-part.php 299

add_action( 'init', 'register_block_core_template_part' );

wp-includes/blocks/term-count.php 80

add_action( 'init', 'register_block_core_term_count' );

wp-includes/blocks/term-description.php 61

add_action( 'init', 'register_block_core_term_description' );

wp-includes/blocks/term-name.php 81

add_action( 'init', 'register_block_core_term_name' );

wp-includes/blocks/term-template.php 137

add_action( 'init', 'register_block_core_term_template' );

wp-includes/blocks/video.php 91

add_action( 'init', 'register_block_core_video' );

wp-includes/blocks/widget-group.php 62

add_action( 'init', 'register_block_core_widget_group' );

wp-includes/class-wp-customize-manager.php 378

remove_action( 'init', 'wp_cron' );

wp-includes/class-wp-scripts.php 154

add_action( 'init', array( $this, 'init' ), 0 );

wp-includes/connectors.php 846

add_action( 'init', '_wp_register_default_connector_settings', 20 );

wp-includes/connectors.php 891

add_action( 'init', '_wp_connectors_pass_default_keys_to_ai_client', 20 );

wp-includes/default-filters.php 154

add_action( 'init', 'wp_create_initial_comment_meta' );

wp-includes/default-filters.php 371

add_action( 'init', '_register_core_block_patterns_and_categories' );

wp-includes/default-filters.php 372

add_action( 'init', 'check_theme_switched', 99 );

wp-includes/default-filters.php 373

add_action( 'init', array( 'WP_Block_Supports', 'init' ), 22 );

wp-includes/default-filters.php 413

add_action( 'init', 'wp_cron' );

wp-includes/default-filters.php 440

add_action( 'init', 'smilies_init', 5 );

wp-includes/default-filters.php 459

add_action( 'init', 'wp_schedule_delete_old_privacy_export_files' );

wp-includes/default-filters.php 461

add_action( 'init', 'wp_schedule_personal_data_cleanup_requests' );

wp-includes/default-filters.php 493

add_action( 'init', '_show_post_preview' );

wp-includes/default-filters.php 545

add_action( 'init', 'rest_api_init' );

wp-includes/default-filters.php 556

add_action( 'init', '_wp_connectors_init', 15 );

wp-includes/default-filters.php 559

add_action( 'init', 'wp_sitemaps_get_server' );

wp-includes/default-filters.php 579

add_action( 'init', 'wp_initialize_site_preview_hooks', 1 );

wp-includes/default-filters.php 591

add_action( 'init', 'create_initial_post_types', 0 ); // Highest priority.

wp-includes/default-filters.php 606

add_action( 'init', 'kses_init' );

wp-includes/default-filters.php 671

add_action( 'init', '_wp_footnotes_kses_init' );

wp-includes/default-filters.php 683

add_action( 'init', 'create_initial_taxonomies', 0 ); // Highest priority.

wp-includes/default-filters.php 709

add_action( 'init', 'wp_widgets_init', 1 );

wp-includes/default-filters.php 794

add_action( 'init', 'wp_register_persisted_preferences_meta' );

wp-includes/default-filters.php 797

add_action( 'init', 'wp_create_initial_post_meta' );

wp-includes/default-filters.php 815

add_action( 'init', '_wp_register_default_font_collections' );

wp-includes/default-filters.php 818

add_action( 'init', '_wp_register_default_icon_collections', 0 );

wp-includes/default-filters.php 819

add_action( 'init', '_wp_register_default_icons' );

wp-includes/ms-default-filters.php 16

add_action( 'init', 'ms_subdomain_constants' );

wp-includes/ms-default-filters.php 25

add_action( 'init', 'maybe_add_existing_user_to_blog' );

wp-includes/theme-previews.php 90

add_action( 'init', 'wp_attach_theme_preview_middleware' );

wp-includes/update.php 1210

add_action( 'init', 'wp_schedule_update_checks' );