A scalable fulfillment system is presented that supports business processes, manages the transport and processing of business-related messages or documents between a business entity and clients, such as customers, vendors, and business partners, and generally supports business document processing. The system intelligently manages the transportation of files from clients, through processing of files, to generating responses that return to the clients. To accommodate a heterogeneous interfacing and processing with different clients in a central system, a file normalization technique is used that captures a common meta-data format from the numerous heterogeneous file types used by numerous clients. The meta-data files, also referred to as messages, contain links to their associated data files and are processed separately. Once the messages are entered into the system, an intelligent queue scheduler (IQS) is used to schedule the processing of messages across a scalable resource of processing engines based on normalized file meta-data parameters.