Bulletproof check for page built with Elementor

functions.php.php

<?php // Don't copy this line

$post_id = get_queried_object_id();
$is_elementor = false;
if ( function_exists('did_action') && did_action('elementor/loaded') ) { // Check if Elementor is loaded
	$is_elementor = \Elementor\Plugin::instance()->db->is_built_with_elementor( $post_id );
} else {
	// Fallback when Elementor isn't loaded: check post meta flag
	$is_elementor = get_post_meta( $post_id, '_elementor_edit_mode', true ) === 'builder';
}

if ( $is_elementor ) {
    // Page is built with Elementor
}