Editing Windows API (section)

{{Short description|Microsoft's core set of application programming interfaces on Windows}}
{{Use mdy dates|date=November 2023}} {{Use American English|date=November 2023}}
{{Infobox software
| logo                   = 
| screenshot             = Windows_2000_architecture.svg
| screenshot size        =
| caption                = The [[Win32]] subsystem shown next to the [[Microsoft POSIX subsystem|POSIX]] and [[OS/2 subsystem]] in the [[architecture of Windows NT]] (later [[Win64]] is also available.)
| author                 = 
| developer              = [[Microsoft]]
| released               = {{Start date and years ago|1985|11|20}}
| latest release version = 
| latest release date    = 
| latest preview version = 
| latest preview date    = 
| replaces               = [[DOS API]]
| operating system       = [[Microsoft Windows]], [[OS/2]]
| platform               = 
| genre                  = [[API]]
| license                = [[Proprietary software|Proprietary]]
| website                = {{URL|https://learn.microsoft.com/windows/apps/}}
}}

The '''Windows API''', informally '''WinAPI''', is the foundational [[API|application programming interface (API)]] that allows a [[computer program]] to access the features of the [[Microsoft Windows]] [[operating system]] in which the program is running. Programs can access API functionality via [[Shared library|shared-library]] technologies or via [[Microsoft Windows library files|system-file]] access.{{Disputed inline|How are "Microsoft Windows library files" not shared libraries?|date=February 2025}}

Each major version of the Windows API has a distinct name that identifies a compatibility aspect of that version. For example, Win32 is the major version of Windows API that runs on 32-bit systems. The name, Windows API, collectively refers to all versions of this capability of Windows.

Microsoft provides developer support via a [[software development kit]], [[Microsoft Windows SDK]], which includes documentation and tools for building software based on the Windows API.