Virus Application Programming Interface, or
Virus API (VAPI) is also referred to as
Antivirus
API (AVAPI), or
Virus Scanning API (VSAPI).
Virus Scanning API 1.0 was introduced in Microsoft Exchange Server 5.5
Service Pack 3 (SP3) and was standard until the
release of Exchange 2000. Many improvements have been made to Virus Scanning API
1.0 to improve performance with Exchange Server. When you use a VAPI scanner and
a client tries to open a message,
a comparison is made to make sure that the message body and attachment have been
scanned by the current virus signature file.
If the current vendor or signature file has not scanned the content, the
corresponding message component is submitted to the
antivirus software vendor for scanning
before that message component is released to the client. [Source:
Microsoft help & Support]
See also API.