Retrieve Order ID Using _order_number Metadata via WooCommerce REST API - By WebToffee (Sequential Order Number for WooCommerce)

functions.php

<?php //Do not copy this line of code

/*You can fetch the Order ID based on the _order_number metadata using WooCommerce's REST API. To do this, use the following API endpoint:
wp-json/wc/v3/orders?meta_key=_order_number&meta_value=123
Simply replace 123 with the desired order number to retrieve the corresponding Order ID.*/

add_filter( 'woocommerce_rest_shop_order_object_query', function( $args, $request ) {
	if (! empty($request['meta_key'] ) &&! empty( $request['meta_value'] ) ) {
		$args ['meta_query'] = array(
			array (
				'key' => sanitize_text_field( $request ['meta_key'] ),
				'value' => sanitize_text_field( $request ['meta_value'] ),
				'compare' => '='
			),
		);
		return $args;
	}
}, 10, 2);

You can fetch the Order ID based on the _order_number metadata using WooCommerce's REST API. To do this, use the following API endpoint:
wp-json/wc/v3/orders?meta_key=_order_number&meta_value=123
Simply replace 123 with the desired order number to retrieve the corresponding Order ID.