WordPress at a glance
action is not described

init action-hook . WP 1.5.0

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

Most of WP is loaded at this stage, and the user is authenticated. WP continues to load on the 'init' hook that follows (e.g. widgets), and many plugins instantiate themselves on it for all sorts of reasons (e.g. they need a user, a taxonomy, etc.).

If you wish to plug an action once WP is loaded, use the 'wp_loaded' hook below.

Usage

add_action( 'init', 'action_function_name_2165' );
function action_function_name_2165(){
	// action...
}

Where the hook is called

In file: /wp-settings.php
init
wp-settings.php 467
do_action( 'init' );

Where the hook is used (in WP core)

wp-includes/update.php 762
add_action( 'init', 'wp_schedule_update_checks' );
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/default-filters.php 290
add_action( 'init', 'check_theme_switched', 99 );
wp-includes/default-filters.php 318
add_action( 'init', 'wp_cron' );
wp-includes/default-filters.php 334
add_action( 'init', 'smilies_init', 5 );
wp-includes/default-filters.php 354
add_action( 'init', 'wp_schedule_delete_old_privacy_export_files' );
wp-includes/default-filters.php 384
add_action( 'init', '_show_post_preview' );
wp-includes/default-filters.php 432
add_action( 'init', 'rest_api_init' );
wp-includes/default-filters.php 460
add_action( 'init', 'create_initial_post_types', 0 ); // highest priority
wp-includes/default-filters.php 474
add_action( 'init', 'kses_init' );
wp-includes/default-filters.php 496
add_action( 'init', 'create_initial_taxonomies', 0 ); // highest priority
wp-includes/default-filters.php 514
add_action( 'init', 'wp_widgets_init', 1 );
wp-includes/blocks/categories.php 102
add_action( 'init', 'register_block_core_categories' );
wp-includes/blocks/archives.php 147
add_action( 'init', 'register_block_core_archives' );
wp-includes/blocks/latest-posts.php 132
add_action( 'init', 'register_block_core_latest_posts' );
wp-includes/blocks/shortcode.php 32
add_action( 'init', 'register_block_core_shortcode' );
wp-includes/class.wp-scripts.php 132
add_action( 'init', array( $this, 'init' ), 0 );
wp-includes/class-wp-customize-manager.php 371
remove_action( 'init', 'wp_cron' );