We have an e-commerce website based on Magento v2, and a self-developed online transaction processing system on the backend to process fulfillment requests initiated by Magento.
The self-developed backend system provides APIs, and Magento will call the fulfillment API and send one request per order. The backend system also includes functionality to route the incoming fulfillment transactions to different internal business units for follow-up, redeem, export, or other actions.
This is a legacy system designed by previous engineers, and it works OK; I'm reviewing the system design for possible enhancements.
I'm wondering:
Just let me know if you need more information, and any hints will be highly appreciated.
Magento 2 does support multi-source-inventory (MSI) and has open APIs. However, from what you've described, you probably want an Order Management System (OMS) that can help you manage and route orders.
There are lots of options out there depending on your particular business needs. These include SaaS solutions like Skubana and Veeqo. If these don't match your needs, feel free to share more requirements/details.
Best of luck!