The Commerce Server version 3.0 SDK (Software Development Kit) contains the tools necessary to develop custom order processing components for the Commerce Server order processing pipeline (OPP), the Commerce Interchange Pipeline (CIP), and client payment components (CPCs) for the Microsoft® Wallet control.
The SDK is included in Commerce Server 3.0 and is installed in the \Microsoft Site Server\SiteServer\Commerce\SDK directory under the Site Server installation directory. The SDK is part of the Commerce Server 3.0 Custom installation.