Aspects of the disclosure described herein provide for a streamlined system for developing an order fulfillment process. The system may include a stateless web resource application programming interface (API) supported by a server, which may be configured as an endpoint to receive order requests (e.g., via an e-commerce website) and generate an instance of a complex object based on the order request. The instance of the complex object may be generated according to an invocable action configured at the system and may include one or more nested data types corresponding to order parameters indicated by the order request. The instance of the complex object may be processed according to fulfillment rules to generate a response to the order request. The response to the order request may include an identification of an order fulfillment center, a fulfillment order, etc.