Wordpress (WooCommerce extensions) - Handle new orders

I want to run PHP function when a new order is placed (this function sends the order details via API to another website).

There are a lot of ways how to place an order (CLI, API, directly in the menu or via eshop....). But I don't want to create a single method for every way, it would be ugly and extensive.

So, my question is: Is there any elegant way how to handle new order?

In the worst case, I will survive duplicate method calls, if necessary.

via Chebli Mohamed