Lots and lots of API’s for this customer to connect WooCommerce to the world!
From multiple marketplaces the new orders are fetched and stored in WooCommerce.
Each marketplace has its own custom API developed, that hooks into WooCommerce and the Marketplace. Via cronjobs each half hour or so the new orders are collected from each marketplace. All orders are created and processed in WooCommerce.
Each X periode the orders are then being processed to be send of to the rightful warehouse for dropship-handling of the products. Multiple warehouses are linked, again each with its own created API to send the orders to the warehouses.
Once the orders are placed, the cronjob checks every X time to see if warehouses have already published the tracking-code for the shipment.
If so, the order is updated. And the tracking-code is send back to the marketplace to notify the customer.
Plugin is custom created for WordPress / WooCommerce core hooks and filters. And in such way that new warehouses/marketplaces can be hooked in pretty easy to extend the whole system and be ready for the future.