# Tutorial: Designing a Purchase Order Processing System by Using AquaLogic Integrator

# Developing the PO Application System

This part describes how to develop the Purchase Order (PO) Processing System by creating the required artifacts from scratch.

It discusses the following topics:

- Getting Started.
- Creating a PurchaseOrder Fulfillment System and Invoking External Services.
- Creating Business Service Endpoint for PurchaseOrderFulfillmentJPD.
- Creating Proxy Service to Invoke a JPD.
- Aggregating the Purchase Order Fulfillment Results.
- Using JPD Transport Callback.
- Actionable Exception Management.