Active Directory Service Interfaces (ADSI) provides a simple, powerful, object-oriented interface to Active Directory. ADSI makes it easy for programmers and administrators to create directory programs by using high-level tools, such as Microsoft Visual Basic, without having to worry about the underlying differences between the different namespaces.

ADSI enables you to build or buy programs that give you a single point of access to multiple directories in your network environment, whether those directories are based on LDAP or another protocol. ADSI is fully scriptable for ease of use by administrators.

For more information about ADSI, see the Active Directory Programmer's Guide at the Microsoft Web site and the Using the Windows Deployment and Resource Kits.

Active Directory also provides support for Messaging Application Programming Interface (MAPI), so legacy MAPI programs will continue to work with Active Directory.

In addition, Active Directory supports the LDAP C API as a lower-level interface for C programmers. For more information, see the Lightweight Directory Access Protocol (LDAP) API at the Microsoft Web site.