WooCommerce order created via REST – sending the date_created along

date_created is read-only value meaning that you cannot set it over the REST API. What you can do is:

  1. Send creation time from your “external system” as order meta data (sample PHP code below) and then in WooCommerce trigger the action using custom plug-in which updates order date_created according to a meta value.
$json_encode['meta_data'][0]['key'] = 'my_date_created';
$json_encode['meta_data'][0]['value'] = '05-12-2017 13:00:00';
  1. Update date_created in your “external system” with date_created from jSon returned by Woocommerce in order to have values synchronised.

If you just want to pair order records do it over order ID returned in jSon by Woocommerce (Woocommerce returns a jSon when the order was created successfully). You will add order ID record to your “external system”.