register_new_user action-hook . WP 4.4.0

Fires after a new user registration has been recorded.

Usage

add_action( 'register_new_user', 'action_function_name_1976' );
function action_function_name_1976( $user_id ){
	// action...
}

$user_id(int)

ID of the newly registered user.

Where the hook is called

do_action( 'register_new_user', $user_id );

Where the hook is used (in WP core)

add_action( 'register_new_user', 'wp_send_new_user_notifications' );