Core Windows API for building traditional desktop applications using C and C++. Win32 provides direct access to system-level functionality including window management, graphics, networking, and hardware.
openapi: 3.1.0
info:
title: Microsoft Windows 10 Win32 API
description: >-
Core Windows API for building traditional desktop applications using C and C++.
Win32 provides direct access to system-level functionality including window
management, graphics, networking, and hardware. This specification models
the major Win32 API categories including User Interface, System Services,
Graphics, Networking, Security, and Devices.
version: 1.0.0
contact:
name: Microsoft Developer Support
url: https://learn.microsoft.com/en-us/windows/win32/
license:
name: Microsoft Software License
url: https://www.microsoft.com/en-us/legal/terms-of-use
externalDocs:
description: Win32 API Reference
url: https://learn.microsoft.com/en-us/windows/win32/api/
servers:
- url: https://api.windows.com
description: Windows Platform API
paths:
/win32/api-categories:
get:
operationId: listWin32ApiCategories
summary: Microsoft Windows 10 List Win32 API categories
description: >-
Retrieves the list of major Win32 API categories including User Interface,
Windows Environment (Shell), User Input and Messaging, Data Access and
Storage, Diagnostics, Graphics and Multimedia, Devices, System Services,
Security and Identity, Networking and Internet, and System Administration.
tags:
- API Categories
responses:
'200':
description: Successful retrieval of API categories
content:
application/json:
schema:
type: array
items:
$ref: '#/components/schemas/ApiCategory'
'401':
description: Unauthorized
/win32/api-categories/{categoryId}/functions:
get:
operationId: listCategoryFunctions
summary: Microsoft Windows 10 List functions in a category
description: >-
Retrieves the list of Win32 API functions within a specified category.
Each function includes its DLL, parameters, return type, and minimum
supported version information.
tags:
- Functions
parameters:
- name: categoryId
in: path
required: true
description: The API category identifier
schema:
type: string
- name: dll
in: query
required: false
description: Filter by DLL name (e.g., kernel32.dll, user32.dll)
schema:
type: string
responses:
'200':
description: Successful retrieval of functions
content:
application/json:
schema:
type: array
items:
$ref: '#/components/schemas/Win32Function'
'404':
description: Category not found
/win32/functions/{functionName}:
get:
operationId: getWin32FunctionDetails
summary: Microsoft Windows 10 Get Win32 function details
description: >-
Retrieves detailed information about a specific Win32 function including
its syntax, parameters, return value, remarks, requirements (minimum
supported client/server, header, library, DLL), and related functions.
tags:
- Functions
parameters:
- name: functionName
in: path
required: true
description: The function name (e.g., CreateWindowExW, SendMessage)
schema:
type: string
responses:
'200':
description: Successful retrieval of function details
content:
application/json:
schema:
$ref: '#/components/schemas/Win32FunctionDetail'
'404':
description: Function not found
/win32/structures/{structureName}:
get:
operationId: getWin32Structure
summary: Microsoft Windows 10 Get Win32 structure definition
description: >-
Retrieves the definition of a Win32 data structure, including its
fields, sizes, alignment requirements, and associated API functions.
tags:
- Structures
parameters:
- name: structureName
in: path
required: true
description: The structure name (e.g., WNDCLASSEXW, MSG, RECT)
schema:
type: string
responses:
'200':
description: Successful retrieval of structure definition
content:
application/json:
schema:
$ref: '#/components/schemas/Win32Structure'
'404':
description: Structure not found
/win32/messages:
get:
operationId: listWindowMessages
summary: Microsoft Windows 10 List window messages
description: >-
Retrieves the list of Win32 window messages (WM_*) used for inter-window
communication. Includes system-defined messages for window management,
user input, and application-defined messages.
tags:
- Messages
parameters:
- name: prefix
in: query
required: false
description: Filter messages by prefix (e.g., WM_, BM_, CB_)
schema:
type: string
responses:
'200':
description: Successful retrieval of messages
content:
application/json:
schema:
type: array
items:
$ref: '#/components/schemas/WindowMessage'
components:
schemas:
ApiCategory:
type: object
description: A major Win32 API category
properties:
id:
type: string
description: Category identifier
name:
type: string
description: Category name
example: User Interface
description:
type: string
description: Category description
subcategories:
type: array
items:
type: object
properties:
name:
type: string
description:
type: string
referenceUrl:
type: string
format: uri
functionCount:
type: integer
description: Number of functions in this category
required:
- id
- name
Win32Function:
type: object
description: A Win32 API function
properties:
name:
type: string
description: Function name
example: CreateWindowExW
dll:
type: string
description: DLL that exports the function
example: user32.dll
header:
type: string
description: Header file declaring the function
example: winuser.h
category:
type: string
description: API category
description:
type: string
description: Brief description of the function
minClientVersion:
type: string
description: Minimum supported client version
example: Windows 10
required:
- name
- dll
Win32FunctionDetail:
type: object
description: Detailed Win32 function information
properties:
name:
type: string
description: Function name
syntax:
type: string
description: Function signature in C/C++
parameters:
type: array
items:
$ref: '#/components/schemas/FunctionParameter'
returnValue:
type: object
properties:
type:
type: string
description:
type: string
remarks:
type: string
description: Additional notes and usage guidance
requirements:
$ref: '#/components/schemas/FunctionRequirements'
relatedFunctions:
type: array
items:
type: string
required:
- name
- syntax
FunctionParameter:
type: object
properties:
name:
type: string
type:
type: string
direction:
type: string
enum:
- in
- out
- inout
description:
type: string
optional:
type: boolean
FunctionRequirements:
type: object
properties:
minimumSupportedClient:
type: string
example: Windows 10 [desktop apps only]
minimumSupportedServer:
type: string
example: Windows Server 2016
header:
type: string
example: winuser.h
library:
type: string
example: User32.lib
dll:
type: string
example: User32.dll
Win32Structure:
type: object
description: A Win32 data structure
properties:
name:
type: string
description: Structure name
fields:
type: array
items:
type: object
properties:
name:
type: string
type:
type: string
description:
type: string
sizeInBytes:
type: integer
description: Size of the structure in bytes
header:
type: string
description: Header file defining the structure
required:
- name
- fields
WindowMessage:
type: object
description: A Win32 window message
properties:
name:
type: string
description: Message constant name
example: WM_CREATE
value:
type: string
description: Numeric value of the message
example: "0x0001"
description:
type: string
description: Description of when the message is sent
wParam:
type: string
description: Meaning of the wParam parameter
lParam:
type: string
description: Meaning of the lParam parameter
required:
- name
- value
tags:
- name: API Categories
- name: Functions
- name: Messages
- name: Structures