Business API (BAPI) is the most important component of SAP Business Framework. BAPI enables SAP and third party applications to interact and integrate with each other at the Business Object / Process level.
Till some time back, SAP was deep into its not-so-friendly interface and architecture, which it inherited from the IBM Mainframe based parent system. But now it has come up with truly platform independent business object interfaces using BAPIs. Business Objects and BAPIs provide an object-oriented view of SAP’s business functionality.
BAPIs are implemented using Remotely callable Function modules. These RFCs are assigned as a callable method of a Business Object in the Business Object Repository (BOR). All BAPIs are independent of the screen and hence can work in the background without user intervention. BAPI supports both inbound and outbound processing. Since it follows object-oriented approach, SAP has positioned itself to support interfacing through BAPIs in the future.