The key to SAP R/3 success was the strategy of making open solutions, in which the applications can run on multiple operating systems, databases, and communication technologies. This enables customers to remain independent of single vendor if they wish.

The figure shows all current SAP supported systems. For an update of supported systems, contact SAP or ask any system vendor.

What basically makes system open is the use of standard formats for data exchange,  communication interfaces, and program - to - program communication. SAP extends the openness concept in several
respects:
                 

• At the system level.  Support for multiple operating systems platforms such as Unix, WindowsNT and AS/400. Supports large number of standard GUIs (User interfaces) such as Windows 3.1, Windows 95, Windows NT, Macintosh, Motif and OS/2 Presentation Manager.
• At the database level. R/3 supports various relational database systems such as Oracle, Informix, Adabas D, DB2, and SQL-Server. Access to the data managed by R/3 is possible using standard R/3 reports as well as any  other SQL standard tool: ODBC, SQL browsers, and so on. SAP has incorporated the standard ANSI-SQL as  the database manipulation language, which allows users and programmers to store, view, and retrieve data to and  from all different underlaying database products.
• At the application level. The system is open to be enhanced and extends to meet specific business requirements. The ABAP/4 repository and R/3 reference model enables users to understand the relationships and inner working of R/3 applications  The R/3 programming interface lets other R/3 systems and external programs invoke R/3 function modules via RFCs (Remote Function Calls). SAP offers the RFC SDK, a standard interface for customers and independent software venders to carry out individual extensions to SAP business applications that support the direct communication with the function modules of R/3.
• At the desktop level. With the development of microsoft OLE technology, R/3 enables desktop users to access SAP data and functions many OLE client programs.
• At Communication protocol level. SAP can use the standard communication protocols TCP/IP, SNA-LU6.2, CPIC and OSF/DCE/DME for inter program communications as well as for network communication and data transfer.

• R/3 includes EDI (Electronic data interchange) interfaces to automate the exchange of data (invoices, orders, etc.,) between R/3 and other applications systems used by business partners.
• It also uses MAPI technology, supporting standard x.400 and SMTP protocols. These standards allow R/3 users to communicate with other mail systems and Internet.
• With ALE technology , SAP R/3 allows communication between distributed applications: R/3-R/3 systems, R/3-R/2 systems, R/3 external application systems.
• Using development environments such as standard ANSI C, C++, Visual Basic, developers can integrate external applications with the R/3 system, exchanging information on the level of business objects.