Antimalware Scan Interface (AMSI)


The Windows Antimalware Scan Interface (AMSI) is a versatile interface standard that allows your applications and services to integrate with any antimalware product that's present on a machine. AMSI provides enhanced malware protection for your end-users and their data, applications, and workloads.

AMSI is agnostic of antimalware vendor; it's designed to allow for the most common malware scanning and protection techniques provided by today's antimalware products that can be integrated into applications. It supports a calling structure allowing for file and memory or stream scanning, content source URL/IP reputation checks, and other techniques.

AMSI also supports the notion of a session so that antimalware vendors can correlate different scan requests. For instance, the different fragments of a malicious payload can be associated to reach a more informed decision, which would be much harder to reach just by looking at those fragments in isolation.

Windows components that integrate with AMSI

The AMSI feature is integrated into these components of Windows 10.

  • User Account Control, or UAC (elevation of EXE, COM, MSI, or ActiveX installation)
  • PowerShell (scripts, interactive use, and dynamic code evaluation)
  • Windows Script Host (wscript.exe and cscript.exe)
  • JavaScript and VBScript
  • Office VBA macros

Developer audience, and sample code

The Antimalware Scan Interface is designed for use by two groups of developers.

  • Application developers who want to make requests to antimalware products from within their apps.
  • Third-party creators of antimalware products who want their products to offer the best features to applications.

For more info, see Developer audience, and sample code.


Starting in Windows 10, version 1903, if your AMSI provider DLL is not Authenticode-signed, then it may not be loaded (depending on how the host machine is configured). For full details, see IAntimalwareProvider interface.

In this section

Topic Description
How AMSI helps you defend against malware As an application developer, you can actively participate in malware defense. Specifically, you can help protect your customers from dynamic script-based malware, and from non-traditional avenues of cyberattack.
Developer audience, samples This topic describes the groups of developers for whom the Antimalware Scan Interface is designed.
Antimalware Scan Interface Reference Enumerations, COM interfaces, and other programming elements of the AMSI API.